ETH Price: $2,268.73 (+4.28%)

Transaction Decoder

Block:
16960483 at Apr-02-2023 09:21:11 AM +UTC
Transaction Fee:
0.001666913160501925 ETH $3.78
Gas Used:
96,275 Gas / 17.314081127 Gwei

Account State Difference:

  Address   Before After State Difference Code
0x5788858E...10EacB84F
0.179016023492539449 Eth
Nonce: 589
0.175349110332037524 Eth
Nonce: 590
0.003666913160501925
0x93c8F944...831Ee4710 0.01 Eth0.012 Eth0.002
(MEV Builder: 0xBaF...e19)
0.733295434723899099 Eth0.733311063070835899 Eth0.0000156283469368

Execution Trace

ETH 0.002 MegumiUnderground.holderMint( holderMintTokens_=[484, 477] )
  • BITRING.ownerOf( tokenId=484 ) => ( 0x5788858ED0aD70DEA5056738b7FfD1810EacB84F )
  • BITRING.ownerOf( tokenId=477 ) => ( 0x5788858ED0aD70DEA5056738b7FfD1810EacB84F )
    File 1 of 2: MegumiUnderground
    /*
    @%%%*=:           %@@@@@@%                                                   .            
    @@@@@%%%*-.       #@@@@@@#                                                                
    @@%%%@@@@%%#+-. ..#@@@@@%#                                                                
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    %%%%%%%%%%%%:%@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@#-                         
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    %%%%%%%%##**@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@%@@@@@@@@@@@-                      
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    */
    pragma solidity ^0.8.13;
    interface IOperatorFilterRegistry {
        function isOperatorAllowed(address registrant, address operator) external view returns (bool);
        function register(address registrant) external;
        function registerAndSubscribe(address registrant, address subscription) external;
        function registerAndCopyEntries(address registrant, address registrantToCopy) external;
        function updateOperator(address registrant, address operator, bool filtered) external;
        function updateOperators(address registrant, address[] calldata operators, bool filtered) external;
        function updateCodeHash(address registrant, bytes32 codehash, bool filtered) external;
        function updateCodeHashes(address registrant, bytes32[] calldata codeHashes, bool filtered) external;
        function subscribe(address registrant, address registrantToSubscribe) external;
        function unsubscribe(address registrant, bool copyExistingEntries) external;
        function subscriptionOf(address addr) external returns (address registrant);
        function subscribers(address registrant) external returns (address[] memory);
        function subscriberAt(address registrant, uint256 index) external returns (address);
        function copyEntriesOf(address registrant, address registrantToCopy) external;
        function isOperatorFiltered(address registrant, address operator) external returns (bool);
        function isCodeHashOfFiltered(address registrant, address operatorWithCode) external returns (bool);
        function isCodeHashFiltered(address registrant, bytes32 codeHash) external returns (bool);
        function filteredOperators(address addr) external returns (address[] memory);
        function filteredCodeHashes(address addr) external returns (bytes32[] memory);
        function filteredOperatorAt(address registrant, uint256 index) external returns (address);
        function filteredCodeHashAt(address registrant, uint256 index) external returns (bytes32);
        function isRegistered(address addr) external returns (bool);
        function codeHashOf(address addr) external returns (bytes32);
    }
    // File: OperatorFilterer.sol
    pragma solidity ^0.8.13;
    abstract contract OperatorFilterer {
        error OperatorNotAllowed(address operator);
        IOperatorFilterRegistry constant operatorFilterRegistry =
            IOperatorFilterRegistry(0x000000000000AAeB6D7670E522A718067333cd4E);
        constructor(address subscriptionOrRegistrantToCopy, bool subscribe) {
            // If an inheriting token contract is deployed to a network without the registry deployed, the modifier
            // will not revert, but the contract will need to be registered with the registry once it is deployed in
            // order for the modifier to filter addresses.
            if (address(operatorFilterRegistry).code.length > 0) {
                if (subscribe) {
                    operatorFilterRegistry.registerAndSubscribe(address(this), subscriptionOrRegistrantToCopy);
                } else {
                    if (subscriptionOrRegistrantToCopy != address(0)) {
                        operatorFilterRegistry.registerAndCopyEntries(address(this), subscriptionOrRegistrantToCopy);
                    } else {
                        operatorFilterRegistry.register(address(this));
                    }
                }
            }
        }
        modifier onlyAllowedOperator(address from) virtual {
            // Check registry code length to facilitate testing in environments without a deployed registry.
            if (address(operatorFilterRegistry).code.length > 0) {
                // Allow spending tokens from addresses with balance
                // Note that this still allows listings and marketplaces with escrow to transfer tokens if transferred
                // from an EOA.
                if (from == msg.sender) {
                    _;
                    return;
                }
                if (
                    !(
                        operatorFilterRegistry.isOperatorAllowed(address(this), msg.sender)
                            && operatorFilterRegistry.isOperatorAllowed(address(this), from)
                    )
                ) {
                    revert OperatorNotAllowed(msg.sender);
                }
            }
            _;
        }
    }
    // File: DefaultOperatorFilterer.sol
    pragma solidity ^0.8.13;
    abstract contract DefaultOperatorFilterer is OperatorFilterer {
        address constant DEFAULT_SUBSCRIPTION = address(0x3cc6CddA760b79bAfa08dF41ECFA224f810dCeB6);
        constructor() OperatorFilterer(DEFAULT_SUBSCRIPTION, true) {}
    }
    // File: @openzeppelin/contracts/utils/Strings.sol
    // OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev String operations.
     */
    library Strings {
        bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
        /**
         * @dev Converts a `uint256` to its ASCII `string` decimal representation.
         */
        function toString(uint256 value) internal pure returns (string memory) {
            // Inspired by OraclizeAPI's implementation - MIT licence
            // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
            if (value == 0) {
                return "0";
            }
            uint256 temp = value;
            uint256 digits;
            while (temp != 0) {
                digits++;
                temp /= 10;
            }
            bytes memory buffer = new bytes(digits);
            while (value != 0) {
                digits -= 1;
                buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                value /= 10;
            }
            return string(buffer);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
         */
        function toHexString(uint256 value) internal pure returns (string memory) {
            if (value == 0) {
                return "0x00";
            }
            uint256 temp = value;
            uint256 length = 0;
            while (temp != 0) {
                length++;
                temp >>= 8;
            }
            return toHexString(value, length);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
         */
        function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
            bytes memory buffer = new bytes(2 * length + 2);
            buffer[0] = "0";
            buffer[1] = "x";
            for (uint256 i = 2 * length + 1; i > 1; --i) {
                buffer[i] = _HEX_SYMBOLS[value & 0xf];
                value >>= 4;
            }
            require(value == 0, "Strings: hex length insufficient");
            return string(buffer);
        }
    }
    // File: @openzeppelin/contracts/utils/Address.sol
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
    pragma solidity ^0.8.1;
    /**
     * @dev Collection of functions related to the address type
     */
    library Address {
        /**
         * @dev Returns true if `account` is a contract.
         *
         * [IMPORTANT]
         * ====
         * It is unsafe to assume that an address for which this function returns
         * false is an externally-owned account (EOA) and not a contract.
         *
         * Among others, `isContract` will return false for the following
         * types of addresses:
         *
         *  - an externally-owned account
         *  - a contract in construction
         *  - an address where a contract will be created
         *  - an address where a contract lived, but was destroyed
         * ====
         *
         * [IMPORTANT]
         * ====
         * You shouldn't rely on `isContract` to protect against flash loan attacks!
         *
         * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
         * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
         * constructor.
         * ====
         */
        function isContract(address account) internal view returns (bool) {
            // This method relies on extcodesize/address.code.length, which returns 0
            // for contracts in construction, since the code is only stored at the end
            // of the constructor execution.
            return account.code.length > 0;
        }
        /**
         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
         * `recipient`, forwarding all available gas and reverting on errors.
         *
         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
         * of certain opcodes, possibly making contracts go over the 2300 gas limit
         * imposed by `transfer`, making them unable to receive funds via
         * `transfer`. {sendValue} removes this limitation.
         *
         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
         *
         * IMPORTANT: because control is transferred to `recipient`, care must be
         * taken to not create reentrancy vulnerabilities. Consider using
         * {ReentrancyGuard} or the
         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
         */
        function sendValue(address payable recipient, uint256 amount) internal {
            require(address(this).balance >= amount, "Address: insufficient balance");
            (bool success, ) = recipient.call{value: amount}("");
            require(success, "Address: unable to send value, recipient may have reverted");
        }
        /**
         * @dev Performs a Solidity function call using a low level `call`. A
         * plain `call` is an unsafe replacement for a function call: use this
         * function instead.
         *
         * If `target` reverts with a revert reason, it is bubbled up by this
         * function (like regular Solidity function calls).
         *
         * Returns the raw returned data. To convert to the expected return value,
         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
         *
         * Requirements:
         *
         * - `target` must be a contract.
         * - calling `target` with `data` must not revert.
         *
         * _Available since v3.1._
         */
        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionCall(target, data, "Address: low-level call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
         * `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, 0, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but also transferring `value` wei to `target`.
         *
         * Requirements:
         *
         * - the calling contract must have an ETH balance of at least `value`.
         * - the called Solidity function must be `payable`.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
        }
        /**
         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
         * with `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(address(this).balance >= value, "Address: insufficient balance for call");
            require(isContract(target), "Address: call to non-contract");
            (bool success, bytes memory returndata) = target.call{value: value}(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
            return functionStaticCall(target, data, "Address: low-level static call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal view returns (bytes memory) {
            require(isContract(target), "Address: static call to non-contract");
            (bool success, bytes memory returndata) = target.staticcall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(isContract(target), "Address: delegate call to non-contract");
            (bool success, bytes memory returndata) = target.delegatecall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
         * revert reason using the provided one.
         *
         * _Available since v4.3._
         */
        function verifyCallResult(
            bool success,
            bytes memory returndata,
            string memory errorMessage
        ) internal pure returns (bytes memory) {
            if (success) {
                return returndata;
            } else {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
    }
    // File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)
    pragma solidity ^0.8.0;
    /**
     * @title ERC721 token receiver interface
     * @dev Interface for any contract that wants to support safeTransfers
     * from ERC721 asset contracts.
     */
    interface IERC721Receiver {
        /**
         * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
         * by `operator` from `from`, this function is called.
         *
         * It must return its Solidity selector to confirm the token transfer.
         * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
         *
         * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
         */
        function onERC721Received(
            address operator,
            address from,
            uint256 tokenId,
            bytes calldata data
        ) external returns (bytes4);
    }
    // File: @openzeppelin/contracts/utils/introspection/IERC165.sol
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Interface of the ERC165 standard, as defined in the
     * https://eips.ethereum.org/EIPS/eip-165[EIP].
     *
     * Implementers can declare support of contract interfaces, which can then be
     * queried by others ({ERC165Checker}).
     *
     * For an implementation, see {ERC165}.
     */
    interface IERC165 {
        /**
         * @dev Returns true if this contract implements the interface defined by
         * `interfaceId`. See the corresponding
         * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
         * to learn more about how these ids are created.
         *
         * This function call must use less than 30 000 gas.
         */
        function supportsInterface(bytes4 interfaceId) external view returns (bool);
    }
    // File: @openzeppelin/contracts/utils/introspection/ERC165.sol
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Implementation of the {IERC165} interface.
     *
     * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
     * for the additional interface id that will be supported. For example:
     *
     * ```solidity
     * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
     *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
     * }
     * ```
     *
     * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
     */
    abstract contract ERC165 is IERC165 {
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
            return interfaceId == type(IERC165).interfaceId;
        }
    }
    // File: @openzeppelin/contracts/token/ERC721/IERC721.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Required interface of an ERC721 compliant contract.
     */
    interface IERC721 is IERC165 {
        /**
         * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
         */
        event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
        /**
         * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
         */
        event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
        /**
         * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
         */
        event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
        /**
         * @dev Returns the number of tokens in ``owner``'s account.
         */
        function balanceOf(address owner) external view returns (uint256 balance);
        /**
         * @dev Returns the owner of the `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function ownerOf(uint256 tokenId) external view returns (address owner);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Transfers `tokenId` token from `from` to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         *
         * Emits a {Transfer} event.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Gives permission to `to` to transfer `tokenId` token to another account.
         * The approval is cleared when the token is transferred.
         *
         * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
         *
         * Requirements:
         *
         * - The caller must own the token or be an approved operator.
         * - `tokenId` must exist.
         *
         * Emits an {Approval} event.
         */
        function approve(address to, uint256 tokenId) external;
        /**
         * @dev Returns the account approved for `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function getApproved(uint256 tokenId) external view returns (address operator);
        /**
         * @dev Approve or remove `operator` as an operator for the caller.
         * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
         *
         * Requirements:
         *
         * - The `operator` cannot be the caller.
         *
         * Emits an {ApprovalForAll} event.
         */
        function setApprovalForAll(address operator, bool _approved) external;
        /**
         * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
         *
         * See {setApprovalForAll}
         */
        function isApprovedForAll(address owner, address operator) external view returns (bool);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes calldata data
        ) external;
    }
    // File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
    pragma solidity ^0.8.0;
    /**
     * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
     * @dev See https://eips.ethereum.org/EIPS/eip-721
     */
    interface IERC721Metadata is IERC721 {
        /**
         * @dev Returns the token collection name.
         */
        function name() external view returns (string memory);
        /**
         * @dev Returns the token collection symbol.
         */
        function symbol() external view returns (string memory);
        /**
         * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
         */
        function tokenURI(uint256 tokenId) external view returns (string memory);
    }
    // File: @openzeppelin/contracts/utils/Context.sol
    // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Provides information about the current execution context, including the
     * sender of the transaction and its data. While these are generally available
     * via msg.sender and msg.data, they should not be accessed in such a direct
     * manner, since when dealing with meta-transactions the account sending and
     * paying for execution may not be the actual sender (as far as an application
     * is concerned).
     *
     * This contract is only required for intermediate, library-like contracts.
     */
    abstract contract Context {
        function _msgSender() internal view virtual returns (address) {
            return msg.sender;
        }
        function _msgData() internal view virtual returns (bytes calldata) {
            return msg.data;
        }
    }
    // File: contracts/erc721a.sol
    // Creator: Chiru Labs
    pragma solidity ^0.8.4;
    error ApprovalCallerNotOwnerNorApproved();
    error ApprovalQueryForNonexistentToken();
    error ApproveToCaller();
    error ApprovalToCurrentOwner();
    error BalanceQueryForZeroAddress();
    error MintToZeroAddress();
    error MintZeroQuantity();
    error OwnerQueryForNonexistentToken();
    error TransferCallerNotOwnerNorApproved();
    error TransferFromIncorrectOwner();
    error TransferToNonERC721ReceiverImplementer();
    error TransferToZeroAddress();
    error URIQueryForNonexistentToken();
    /**
     * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
     * the Metadata extension. Built to optimize for lower gas during batch mints.
     *
     * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
     *
     * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
     *
     * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
     */
    contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
        using Address for address;
        using Strings for uint256;
        // Compiler will pack this into a single 256bit word.
        struct TokenOwnership {
            // The address of the owner.
            address addr;
            // Keeps track of the start time of ownership with minimal overhead for tokenomics.
            uint64 startTimestamp;
            // Whether the token has been burned.
            bool burned;
        }
        // Compiler will pack this into a single 256bit word.
        struct AddressData {
            // Realistically, 2**64-1 is more than enough.
            uint64 balance;
            // Keeps track of mint count with minimal overhead for tokenomics.
            uint64 numberMinted;
            // Keeps track of burn count with minimal overhead for tokenomics.
            uint64 numberBurned;
            // For miscellaneous variable(s) pertaining to the address
            // (e.g. number of whitelist mint slots used).
            // If there are multiple variables, please pack them into a uint64.
            uint64 aux;
        }
        // The tokenId of the next token to be minted.
        uint256 internal _currentIndex;
        // The number of tokens burned.
        uint256 internal _burnCounter;
        // Token name
        string private _name;
        // Token symbol
        string private _symbol;
        // Mapping from token ID to ownership details
        // An empty struct value does not necessarily mean the token is unowned. See _ownershipOf implementation for details.
        mapping(uint256 => TokenOwnership) internal _ownerships;
        // Mapping owner address to address data
        mapping(address => AddressData) private _addressData;
        // Mapping from token ID to approved address
        mapping(uint256 => address) private _tokenApprovals;
        // Mapping from owner to operator approvals
        mapping(address => mapping(address => bool)) private _operatorApprovals;
        constructor(string memory name_, string memory symbol_) {
            _name = name_;
            _symbol = symbol_;
            _currentIndex = _startTokenId();
        }
        /**
         * To change the starting tokenId, please override this function.
         */
        function _startTokenId() internal view virtual returns (uint256) {
            return 1;
        }
        /**
         * @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
         */
        function totalSupply() public view returns (uint256) {
            // Counter underflow is impossible as _burnCounter cannot be incremented
            // more than _currentIndex - _startTokenId() times
            unchecked {
                return _currentIndex - _burnCounter - _startTokenId();
            }
        }
        /**
         * Returns the total amount of tokens minted in the contract.
         */
        function _totalMinted() internal view returns (uint256) {
            // Counter underflow is impossible as _currentIndex does not decrement,
            // and it is initialized to _startTokenId()
            unchecked {
                return _currentIndex - _startTokenId();
            }
        }
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
            return
                interfaceId == type(IERC721).interfaceId ||
                interfaceId == type(IERC721Metadata).interfaceId ||
                super.supportsInterface(interfaceId);
        }
        /**
         * @dev See {IERC721-balanceOf}.
         */
        function balanceOf(address owner) public view override returns (uint256) {
            if (owner == address(0)) revert BalanceQueryForZeroAddress();
            return uint256(_addressData[owner].balance);
        }
        /**
         * Returns the number of tokens minted by `owner`.
         */
        function _numberMinted(address owner) internal view returns (uint256) {
            return uint256(_addressData[owner].numberMinted);
        }
        /**
         * Returns the number of tokens burned by or on behalf of `owner`.
         */
        function _numberBurned(address owner) internal view returns (uint256) {
            return uint256(_addressData[owner].numberBurned);
        }
        /**
         * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
         */
        function _getAux(address owner) internal view returns (uint64) {
            return _addressData[owner].aux;
        }
        /**
         * Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
         * If there are multiple variables, please pack them into a uint64.
         */
        function _setAux(address owner, uint64 aux) internal {
            _addressData[owner].aux = aux;
        }
        /**
         * Gas spent here starts off proportional to the maximum mint batch size.
         * It gradually moves to O(1) as tokens get transferred around in the collection over time.
         */
        function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
            uint256 curr = tokenId;
            unchecked {
                if (_startTokenId() <= curr && curr < _currentIndex) {
                    TokenOwnership memory ownership = _ownerships[curr];
                    if (!ownership.burned) {
                        if (ownership.addr != address(0)) {
                            return ownership;
                        }
                        // Invariant:
                        // There will always be an ownership that has an address and is not burned
                        // before an ownership that does not have an address and is not burned.
                        // Hence, curr will not underflow.
                        while (true) {
                            curr--;
                            ownership = _ownerships[curr];
                            if (ownership.addr != address(0)) {
                                return ownership;
                            }
                        }
                    }
                }
            }
            revert OwnerQueryForNonexistentToken();
        }
        /**
         * @dev See {IERC721-ownerOf}.
         */
        function ownerOf(uint256 tokenId) public view override returns (address) {
            return _ownershipOf(tokenId).addr;
        }
        /**
         * @dev See {IERC721Metadata-name}.
         */
        function name() public view virtual override returns (string memory) {
            return _name;
        }
        /**
         * @dev See {IERC721Metadata-symbol}.
         */
        function symbol() public view virtual override returns (string memory) {
            return _symbol;
        }
        /**
         * @dev See {IERC721Metadata-tokenURI}.
         */
        function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
            if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
            string memory baseURI = _baseURI();
            return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
        }
        /**
         * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
         * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
         * by default, can be overriden in child contracts.
         */
        function _baseURI() internal view virtual returns (string memory) {
            return '';
        }
        /**
         * @dev See {IERC721-approve}.
         */
        function approve(address to, uint256 tokenId) public override {
            address owner = ERC721A.ownerOf(tokenId);
            if (to == owner) revert ApprovalToCurrentOwner();
            if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
                revert ApprovalCallerNotOwnerNorApproved();
            }
            _approve(to, tokenId, owner);
        }
        /**
         * @dev See {IERC721-getApproved}.
         */
        function getApproved(uint256 tokenId) public view override returns (address) {
            if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
            return _tokenApprovals[tokenId];
        }
        /**
         * @dev See {IERC721-setApprovalForAll}.
         */
        function setApprovalForAll(address operator, bool approved) public virtual override {
            if (operator == _msgSender()) revert ApproveToCaller();
            _operatorApprovals[_msgSender()][operator] = approved;
            emit ApprovalForAll(_msgSender(), operator, approved);
        }
        /**
         * @dev See {IERC721-isApprovedForAll}.
         */
        function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
            return _operatorApprovals[owner][operator];
        }
        /**
         * @dev See {IERC721-transferFrom}.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            _transfer(from, to, tokenId);
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            safeTransferFrom(from, to, tokenId, '');
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) public virtual override {
            _transfer(from, to, tokenId);
            if (to.isContract() && !_checkContractOnERC721Received(from, to, tokenId, _data)) {
                revert TransferToNonERC721ReceiverImplementer();
            }
        }
        /**
         * @dev Returns whether `tokenId` exists.
         *
         * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
         *
         * Tokens start existing when they are minted (`_mint`),
         */
        function _exists(uint256 tokenId) internal view returns (bool) {
            return _startTokenId() <= tokenId && tokenId < _currentIndex &&
                !_ownerships[tokenId].burned;
        }
        function _safeMint(address to, uint256 quantity) internal {
            _safeMint(to, quantity, '');
        }
        /**
         * @dev Safely mints `quantity` tokens and transfers them to `to`.
         *
         * Requirements:
         *
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
         * - `quantity` must be greater than 0.
         *
         * Emits a {Transfer} event.
         */
        function _safeMint(
            address to,
            uint256 quantity,
            bytes memory _data
        ) internal {
            _mint(to, quantity, _data, true);
        }
        /**
         * @dev Mints `quantity` tokens and transfers them to `to`.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `quantity` must be greater than 0.
         *
         * Emits a {Transfer} event.
         */
        function _mint(
            address to,
            uint256 quantity,
            bytes memory _data,
            bool safe
        ) internal {
            uint256 startTokenId = _currentIndex;
            if (to == address(0)) revert MintToZeroAddress();
            if (quantity == 0) revert MintZeroQuantity();
            _beforeTokenTransfers(address(0), to, startTokenId, quantity);
            // Overflows are incredibly unrealistic.
            // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
            // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
            unchecked {
                _addressData[to].balance += uint64(quantity);
                _addressData[to].numberMinted += uint64(quantity);
                _ownerships[startTokenId].addr = to;
                _ownerships[startTokenId].startTimestamp = uint64(block.timestamp);
                uint256 updatedIndex = startTokenId;
                uint256 end = updatedIndex + quantity;
                if (safe && to.isContract()) {
                    do {
                        emit Transfer(address(0), to, updatedIndex);
                        if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
                            revert TransferToNonERC721ReceiverImplementer();
                        }
                    } while (updatedIndex != end);
                    // Reentrancy protection
                    if (_currentIndex != startTokenId) revert();
                } else {
                    do {
                        emit Transfer(address(0), to, updatedIndex++);
                    } while (updatedIndex != end);
                }
                _currentIndex = updatedIndex;
            }
            _afterTokenTransfers(address(0), to, startTokenId, quantity);
        }
        /**
         * @dev Transfers `tokenId` from `from` to `to`.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         *
         * Emits a {Transfer} event.
         */
        function _transfer(
            address from,
            address to,
            uint256 tokenId
        ) private {
            TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
            if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
            bool isApprovedOrOwner = (_msgSender() == from ||
                isApprovedForAll(from, _msgSender()) ||
                getApproved(tokenId) == _msgSender());
            if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
            if (to == address(0)) revert TransferToZeroAddress();
            _beforeTokenTransfers(from, to, tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, from);
            // Underflow of the sender's balance is impossible because we check for
            // ownership above and the recipient's balance can't realistically overflow.
            // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
            unchecked {
                _addressData[from].balance -= 1;
                _addressData[to].balance += 1;
                TokenOwnership storage currSlot = _ownerships[tokenId];
                currSlot.addr = to;
                currSlot.startTimestamp = uint64(block.timestamp);
                // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
                // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
                uint256 nextTokenId = tokenId + 1;
                TokenOwnership storage nextSlot = _ownerships[nextTokenId];
                if (nextSlot.addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId != _currentIndex) {
                        nextSlot.addr = from;
                        nextSlot.startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(from, to, tokenId);
            _afterTokenTransfers(from, to, tokenId, 1);
        }
        /**
         * @dev This is equivalent to _burn(tokenId, false)
         */
        function _burn(uint256 tokenId) internal virtual {
            _burn(tokenId, false);
        }
        /**
         * @dev Destroys `tokenId`.
         * The approval is cleared when the token is burned.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         *
         * Emits a {Transfer} event.
         */
        function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
            TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
            address from = prevOwnership.addr;
            if (approvalCheck) {
                bool isApprovedOrOwner = (_msgSender() == from ||
                    isApprovedForAll(from, _msgSender()) ||
                    getApproved(tokenId) == _msgSender());
                if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
            }
            _beforeTokenTransfers(from, address(0), tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, from);
            // Underflow of the sender's balance is impossible because we check for
            // ownership above and the recipient's balance can't realistically overflow.
            // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
            unchecked {
                AddressData storage addressData = _addressData[from];
                addressData.balance -= 1;
                addressData.numberBurned += 1;
                // Keep track of who burned the token, and the timestamp of burning.
                TokenOwnership storage currSlot = _ownerships[tokenId];
                currSlot.addr = from;
                currSlot.startTimestamp = uint64(block.timestamp);
                currSlot.burned = true;
                // If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
                // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
                uint256 nextTokenId = tokenId + 1;
                TokenOwnership storage nextSlot = _ownerships[nextTokenId];
                if (nextSlot.addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId != _currentIndex) {
                        nextSlot.addr = from;
                        nextSlot.startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(from, address(0), tokenId);
            _afterTokenTransfers(from, address(0), tokenId, 1);
            // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
            unchecked {
                _burnCounter++;
            }
        }
        /**
         * @dev Approve `to` to operate on `tokenId`
         *
         * Emits a {Approval} event.
         */
        function _approve(
            address to,
            uint256 tokenId,
            address owner
        ) private {
            _tokenApprovals[tokenId] = to;
            emit Approval(owner, to, tokenId);
        }
        /**
         * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
         *
         * @param from address representing the previous owner of the given token ID
         * @param to target address that will receive the tokens
         * @param tokenId uint256 ID of the token to be transferred
         * @param _data bytes optional data to send along with the call
         * @return bool whether the call correctly returned the expected magic value
         */
        function _checkContractOnERC721Received(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) private returns (bool) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert TransferToNonERC721ReceiverImplementer();
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        }
        /**
         * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
         * And also called before burning one token.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
         * transferred to `to`.
         * - When `from` is zero, `tokenId` will be minted for `to`.
         * - When `to` is zero, `tokenId` will be burned by `from`.
         * - `from` and `to` are never both zero.
         */
        function _beforeTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
        /**
         * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
         * minting.
         * And also called after one token has been burned.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
         * transferred to `to`.
         * - When `from` is zero, `tokenId` has been minted for `to`.
         * - When `to` is zero, `tokenId` has been burned by `from`.
         * - `from` and `to` are never both zero.
         */
        function _afterTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
    }
    // File: @openzeppelin/contracts/access/Ownable.sol
    // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Contract module which provides a basic access control mechanism, where
     * there is an account (an owner) that can be granted exclusive access to
     * specific functions.
     *
     * By default, the owner account will be the one that deploys the contract. This
     * can later be changed with {transferOwnership}.
     *
     * This module is used through inheritance. It will make available the modifier
     * `onlyOwner`, which can be applied to your functions to restrict their use to
     * the owner.
     */
    abstract contract Ownable is Context {
        address private _owner;
        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
        /**
         * @dev Initializes the contract setting the deployer as the initial owner.
         */
        constructor() {
            _transferOwnership(_msgSender());
        }
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() public view virtual returns (address) {
            return _owner;
        }
        /**
         * @dev Throws if called by any account other than the owner.
         */
        modifier onlyOwner() {
            require(owner() == _msgSender(), "Ownable: caller is not the owner");
            _;
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Can only be called by the current owner.
         */
        function transferOwnership(address newOwner) public virtual onlyOwner {
            require(newOwner != address(0), "Ownable: new owner is the zero address");
            _transferOwnership(newOwner);
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Internal function without access restriction.
         */
        function _transferOwnership(address newOwner) internal virtual {
            address oldOwner = _owner;
            _owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }
    // File: contracts/contract.sol
    pragma solidity ^0.8.4;
    contract MegumiUnderground is Ownable, ERC721A, DefaultOperatorFilterer  {
        using Strings for uint256;
        string private baseTokenURI;
        uint64 public maxSupply = 555;
        uint256 public publicSaleCost = 0.02 ether;
        uint256 public holderCost = 0.001 ether;
        bool public publicSaleActive = false;
        bool public claimActive = false;
        IERC721 private bitringContract;
        mapping(uint256 => uint256) private claimLib;
        constructor() ERC721A("MEGUMI Underground", "MEGUMI"){
            bitringContract = IERC721(0x36DCEBE5537C23D59945560E216C8aE902d0cD09);
        }
        modifier mintCompliance(uint256 _mintAmount) {
            require(_mintAmount > 0 , "Invalid mint amount!");
            require(totalMinted() + _mintAmount <= maxSupply, "Max supply exceeded!");
            _;
        }
        // Holder Mint
        function holderMint(
            uint256[] calldata holderMintTokens_
        )
            external
            payable
        {
            uint256 quantity_ = holderMintTokens_.length;
            require(claimActive, "Claim is not Active");
            require(quantity_ > 0, "You must mint at least 1");
            require(msg.value >= holderCost * quantity_, "Insufficient funds!");
            require(
                quantity_ <= (maxSupply - totalSupply()),
                "Not enough supply"
            );
            require(
                !usedTokenIds(holderMintTokens_),
                "Token already used"
            );
            for (uint256 i; i < holderMintTokens_.length; i++) {
                require(
                    msg.sender == bitringContract.ownerOf(holderMintTokens_[i]),
                    "Token not owned"
                );
            }
            setUsedTokenIds(holderMintTokens_);
            _safeMint(msg.sender, quantity_);
        }
        ///Allows any address to mint when the public sale is open
        function publicMint(uint64 _mintAmount) public payable mintCompliance(_mintAmount) {
            require(publicSaleActive, "Public is not Active");
            require(tx.origin == msg.sender);
            require(msg.value >= publicSaleCost * _mintAmount, "Insufficient funds!");
            _safeMint(msg.sender, _mintAmount);
        }
        ///Allows owner of the collection to airdrop a token to any address
        function ownerMint(uint256 _mintAmount, address _receiver) public mintCompliance(_mintAmount) onlyOwner {
            _safeMint(_receiver, _mintAmount);
        }
        //@return token ids owned by an address in the collection
        function walletOfOwner(address _owner)
            external
            view
            returns (uint256[] memory)
        {
            uint256 ownerTokenCount = balanceOf(_owner);
            uint256[] memory ownedTokenIds = new uint256[](ownerTokenCount);
            uint256 currentTokenId = 1;
            uint256 ownedTokenIndex = 0;
            while (ownedTokenIndex < ownerTokenCount && currentTokenId <= maxSupply) {
                if(exists(currentTokenId) == true) {
                    address currentTokenOwner = ownerOf(currentTokenId);
                    if (currentTokenOwner == _owner) {
                        ownedTokenIds[ownedTokenIndex] = currentTokenId;
                        ownedTokenIndex++;
                    }
                }
                currentTokenId++;
            }
            return ownedTokenIds;
        }
        function transferFrom(address from, address to, uint256 tokenId) public override onlyAllowedOperator(from) {
            super.transferFrom(from, to, tokenId);
        }
        function safeTransferFrom(address from, address to, uint256 tokenId) public override onlyAllowedOperator(from) {
            super.safeTransferFrom(from, to, tokenId);
        }
        function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data)
            public
            override
            onlyAllowedOperator(from)
        {
            super.safeTransferFrom(from, to, tokenId, data);
        }
        //@return full url for passed in token id 
        function tokenURI(uint256 _tokenId)
            public
            view
            virtual
            override
            returns (string memory)
        {
            require(
            _exists(_tokenId),
            "ERC721Metadata: URI query for nonexistent token"
            );
            string memory currentBaseURI = _baseURI();
            return bytes(currentBaseURI).length > 0
                ? string(abi.encodePacked(currentBaseURI, _tokenId.toString()))
                : "";
        }
        // Utilities
        function packBool(
            uint256 _packedBools,
            uint256 _boolIndex,
            bool _value
        ) public pure returns (uint256) {
            return
                _value
                    ? _packedBools | (uint256(1) << _boolIndex)
                    : _packedBools & ~(uint256(1) << _boolIndex);
        }
        function unPackBool(uint256 _packedBools, uint256 _boolIndex)
            internal
            pure
            returns (bool)
        {
            return (_packedBools >> _boolIndex) & uint256(1) == 1 ? true : false;
        }
        function setUsedTokenIds(
            uint256[] calldata holderMints
        ) public {
            uint256 cRow;
            uint256 cPackedBools = claimLib[0];
            for (uint256 i; i < holderMints.length; i++) {
                (uint256 boolRow, uint256 boolColumn) = freeMintPosition(
                    holderMints[i]
                );
                if (boolRow != cRow) {
                    claimLib[cRow] = cPackedBools;
                    cRow = boolRow;
                    cPackedBools = claimLib[boolRow];
                }
                cPackedBools = packBool(cPackedBools, boolColumn, true);
                if (i + 1 == holderMints.length) {
                    claimLib[cRow] = cPackedBools;
                }
            }
        }
        function usedTokenIds(
            uint256[] calldata holderMints
        ) private view returns (bool) {
            uint256 cRow;
            uint256 cPackedBools = claimLib[0];
            uint256 unpackedBools;
            for (uint256 i; i < holderMints.length; i++) {
                (uint256 boolRow, uint256 boolColumn) = freeMintPosition(
                    holderMints[i]
                );
                if (boolRow != cRow) {
                    if (unpackedBools > 0) return true;
                    cRow = boolRow;
                    cPackedBools = claimLib[boolRow];
                    unpackedBools = 0;
                }
                unpackedBools =
                    unpackedBools |
                    (cPackedBools & (uint256(1) << boolColumn));
                if (i + 1 == holderMints.length) {
                    if (unpackedBools > 0) return true;
                }
            }
            return false;
        }
        function usedTokenId(uint256 tokenId)
            public
            view
            returns (bool freeMintUsed)
        {
            (uint256 boolRow, uint256 boolColumn) = freeMintPosition(tokenId);
            uint256 packedBools = claimLib[boolRow];
            freeMintUsed = (packedBools & (uint256(1) << boolColumn)) > 0
                ? true
                : false;
        }
        function freeMintPosition(uint256 tokenId)
            internal
            pure
            returns (uint256 boolRow, uint256 boolColumn)
        {
            boolRow = (tokenId << 1) / 256;
            boolColumn = (tokenId << 1) % 256;
        }
        function preSalePosition(uint256 tokenId)
            internal
            pure
            returns (uint256 boolRow, uint256 boolColumn)
        {
            (boolRow, boolColumn) = freeMintPosition(tokenId);
            boolColumn++;
        }
        //@return amount an address has minted during all sales
        function numberMinted(address _owner) public view returns (uint256) {
            return _numberMinted(_owner);
        }
        //@return all NFT's minted including burned tokens
        function totalMinted() public view returns (uint256) {
            return _totalMinted();
        }
        function exists(uint256 _tokenId) public view returns (bool) {
            return _exists(_tokenId);
        }
        //@return url for the nft metadata
        function _baseURI() internal view virtual override returns (string memory) {
            return baseTokenURI;
        }
        function setBaseURI(string calldata _URI) external onlyOwner {
            baseTokenURI = _URI;
        }
        
        function setClaimActive(bool _state) public onlyOwner {
            claimActive = _state;
        }
        function setPublicActive(bool _state) public onlyOwner {
            publicSaleActive = _state;
        }
        function withdraw() public onlyOwner {
            (bool os, ) = payable(owner()).call{value: address(this).balance}("");
            require(os);
        }
        /// Fallbacks 
        receive() external payable { }
        fallback() external payable { }
    }

    File 2 of 2: BITRING
    /**
     *Submitted for verification at Etherscan.io on 2023-2-09
    */
    pragma solidity ^0.8.13;
    interface IOperatorFilterRegistry {
        function isOperatorAllowed(address registrant, address operator) external view returns (bool);
        function register(address registrant) external;
        function registerAndSubscribe(address registrant, address subscription) external;
        function registerAndCopyEntries(address registrant, address registrantToCopy) external;
        function updateOperator(address registrant, address operator, bool filtered) external;
        function updateOperators(address registrant, address[] calldata operators, bool filtered) external;
        function updateCodeHash(address registrant, bytes32 codehash, bool filtered) external;
        function updateCodeHashes(address registrant, bytes32[] calldata codeHashes, bool filtered) external;
        function subscribe(address registrant, address registrantToSubscribe) external;
        function unsubscribe(address registrant, bool copyExistingEntries) external;
        function subscriptionOf(address addr) external returns (address registrant);
        function subscribers(address registrant) external returns (address[] memory);
        function subscriberAt(address registrant, uint256 index) external returns (address);
        function copyEntriesOf(address registrant, address registrantToCopy) external;
        function isOperatorFiltered(address registrant, address operator) external returns (bool);
        function isCodeHashOfFiltered(address registrant, address operatorWithCode) external returns (bool);
        function isCodeHashFiltered(address registrant, bytes32 codeHash) external returns (bool);
        function filteredOperators(address addr) external returns (address[] memory);
        function filteredCodeHashes(address addr) external returns (bytes32[] memory);
        function filteredOperatorAt(address registrant, uint256 index) external returns (address);
        function filteredCodeHashAt(address registrant, uint256 index) external returns (bytes32);
        function isRegistered(address addr) external returns (bool);
        function codeHashOf(address addr) external returns (bytes32);
    }
    // File: OperatorFilterer.sol
    pragma solidity ^0.8.13;
    abstract contract OperatorFilterer {
        error OperatorNotAllowed(address operator);
        IOperatorFilterRegistry constant operatorFilterRegistry =
            IOperatorFilterRegistry(0x000000000000AAeB6D7670E522A718067333cd4E);
        constructor(address subscriptionOrRegistrantToCopy, bool subscribe) {
            // If an inheriting token contract is deployed to a network without the registry deployed, the modifier
            // will not revert, but the contract will need to be registered with the registry once it is deployed in
            // order for the modifier to filter addresses.
            if (address(operatorFilterRegistry).code.length > 0) {
                if (subscribe) {
                    operatorFilterRegistry.registerAndSubscribe(address(this), subscriptionOrRegistrantToCopy);
                } else {
                    if (subscriptionOrRegistrantToCopy != address(0)) {
                        operatorFilterRegistry.registerAndCopyEntries(address(this), subscriptionOrRegistrantToCopy);
                    } else {
                        operatorFilterRegistry.register(address(this));
                    }
                }
            }
        }
        modifier onlyAllowedOperator(address from) virtual {
            // Check registry code length to facilitate testing in environments without a deployed registry.
            if (address(operatorFilterRegistry).code.length > 0) {
                // Allow spending tokens from addresses with balance
                // Note that this still allows listings and marketplaces with escrow to transfer tokens if transferred
                // from an EOA.
                if (from == msg.sender) {
                    _;
                    return;
                }
                if (
                    !(
                        operatorFilterRegistry.isOperatorAllowed(address(this), msg.sender)
                            && operatorFilterRegistry.isOperatorAllowed(address(this), from)
                    )
                ) {
                    revert OperatorNotAllowed(msg.sender);
                }
            }
            _;
        }
    }
    // File: DefaultOperatorFilterer.sol
    pragma solidity ^0.8.13;
    abstract contract DefaultOperatorFilterer is OperatorFilterer {
        address constant DEFAULT_SUBSCRIPTION = address(0x3cc6CddA760b79bAfa08dF41ECFA224f810dCeB6);
        constructor() OperatorFilterer(DEFAULT_SUBSCRIPTION, true) {}
    }
    // File: undead-ape-yacht-club.sol
    // File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/MerkleProof.sol
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/MerkleProof.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev These functions deal with verification of Merkle Trees proofs.
     *
     * The proofs can be generated using the JavaScript library
     * https://github.com/miguelmota/merkletreejs[merkletreejs].
     * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
     *
     * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
     *
     * WARNING: You should avoid using leaf values that are 64 bytes long prior to
     * hashing, or use a hash function other than keccak256 for hashing leaves.
     * This is because the concatenation of a sorted pair of internal nodes in
     * the merkle tree could be reinterpreted as a leaf value.
     */
    library MerkleProof {
        /**
         * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
         * defined by `root`. For this, a `proof` must be provided, containing
         * sibling hashes on the branch from the leaf to the root of the tree. Each
         * pair of leaves and each pair of pre-images are assumed to be sorted.
         */
        function verify(
            bytes32[] memory proof,
            bytes32 root,
            bytes32 leaf
        ) internal pure returns (bool) {
            return processProof(proof, leaf) == root;
        }
        /**
         * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
         * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
         * hash matches the root of the tree. When processing the proof, the pairs
         * of leafs & pre-images are assumed to be sorted.
         *
         * _Available since v4.4._
         */
        function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
            bytes32 computedHash = leaf;
            for (uint256 i = 0; i < proof.length; i++) {
                bytes32 proofElement = proof[i];
                if (computedHash <= proofElement) {
                    // Hash(current computed hash + current element of the proof)
                    computedHash = _efficientHash(computedHash, proofElement);
                } else {
                    // Hash(current element of the proof + current computed hash)
                    computedHash = _efficientHash(proofElement, computedHash);
                }
            }
            return computedHash;
        }
        function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
            assembly {
                mstore(0x00, a)
                mstore(0x20, b)
                value := keccak256(0x00, 0x40)
            }
        }
    }
    // File: @openzeppelin/contracts/utils/Strings.sol
    // OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev String operations.
     */
    library Strings {
        bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
        /**
         * @dev Converts a `uint256` to its ASCII `string` decimal representation.
         */
        function toString(uint256 value) internal pure returns (string memory) {
            // Inspired by OraclizeAPI's implementation - MIT licence
            // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
            if (value == 0) {
                return "0";
            }
            uint256 temp = value;
            uint256 digits;
            while (temp != 0) {
                digits++;
                temp /= 10;
            }
            bytes memory buffer = new bytes(digits);
            while (value != 0) {
                digits -= 1;
                buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
                value /= 10;
            }
            return string(buffer);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
         */
        function toHexString(uint256 value) internal pure returns (string memory) {
            if (value == 0) {
                return "0x00";
            }
            uint256 temp = value;
            uint256 length = 0;
            while (temp != 0) {
                length++;
                temp >>= 8;
            }
            return toHexString(value, length);
        }
        /**
         * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
         */
        function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
            bytes memory buffer = new bytes(2 * length + 2);
            buffer[0] = "0";
            buffer[1] = "x";
            for (uint256 i = 2 * length + 1; i > 1; --i) {
                buffer[i] = _HEX_SYMBOLS[value & 0xf];
                value >>= 4;
            }
            require(value == 0, "Strings: hex length insufficient");
            return string(buffer);
        }
    }
    // File: @openzeppelin/contracts/utils/Address.sol
    // OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
    pragma solidity ^0.8.1;
    /**
     * @dev Collection of functions related to the address type
     */
    library Address {
        /**
         * @dev Returns true if `account` is a contract.
         *
         * [IMPORTANT]
         * ====
         * It is unsafe to assume that an address for which this function returns
         * false is an externally-owned account (EOA) and not a contract.
         *
         * Among others, `isContract` will return false for the following
         * types of addresses:
         *
         *  - an externally-owned account
         *  - a contract in construction
         *  - an address where a contract will be created
         *  - an address where a contract lived, but was destroyed
         * ====
         *
         * [IMPORTANT]
         * ====
         * You shouldn't rely on `isContract` to protect against flash loan attacks!
         *
         * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
         * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
         * constructor.
         * ====
         */
        function isContract(address account) internal view returns (bool) {
            // This method relies on extcodesize/address.code.length, which returns 0
            // for contracts in construction, since the code is only stored at the end
            // of the constructor execution.
            return account.code.length > 0;
        }
        /**
         * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
         * `recipient`, forwarding all available gas and reverting on errors.
         *
         * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
         * of certain opcodes, possibly making contracts go over the 2300 gas limit
         * imposed by `transfer`, making them unable to receive funds via
         * `transfer`. {sendValue} removes this limitation.
         *
         * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
         *
         * IMPORTANT: because control is transferred to `recipient`, care must be
         * taken to not create reentrancy vulnerabilities. Consider using
         * {ReentrancyGuard} or the
         * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
         */
        function sendValue(address payable recipient, uint256 amount) internal {
            require(address(this).balance >= amount, "Address: insufficient balance");
            (bool success, ) = recipient.call{value: amount}("");
            require(success, "Address: unable to send value, recipient may have reverted");
        }
        /**
         * @dev Performs a Solidity function call using a low level `call`. A
         * plain `call` is an unsafe replacement for a function call: use this
         * function instead.
         *
         * If `target` reverts with a revert reason, it is bubbled up by this
         * function (like regular Solidity function calls).
         *
         * Returns the raw returned data. To convert to the expected return value,
         * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
         *
         * Requirements:
         *
         * - `target` must be a contract.
         * - calling `target` with `data` must not revert.
         *
         * _Available since v3.1._
         */
        function functionCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionCall(target, data, "Address: low-level call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
         * `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, 0, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but also transferring `value` wei to `target`.
         *
         * Requirements:
         *
         * - the calling contract must have an ETH balance of at least `value`.
         * - the called Solidity function must be `payable`.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value
        ) internal returns (bytes memory) {
            return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
        }
        /**
         * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
         * with `errorMessage` as a fallback revert reason when `target` reverts.
         *
         * _Available since v3.1._
         */
        function functionCallWithValue(
            address target,
            bytes memory data,
            uint256 value,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(address(this).balance >= value, "Address: insufficient balance for call");
            require(isContract(target), "Address: call to non-contract");
            (bool success, bytes memory returndata) = target.call{value: value}(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
            return functionStaticCall(target, data, "Address: low-level static call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a static call.
         *
         * _Available since v3.3._
         */
        function functionStaticCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal view returns (bytes memory) {
            require(isContract(target), "Address: static call to non-contract");
            (bool success, bytes memory returndata) = target.staticcall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
            return functionDelegateCall(target, data, "Address: low-level delegate call failed");
        }
        /**
         * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
         * but performing a delegate call.
         *
         * _Available since v3.4._
         */
        function functionDelegateCall(
            address target,
            bytes memory data,
            string memory errorMessage
        ) internal returns (bytes memory) {
            require(isContract(target), "Address: delegate call to non-contract");
            (bool success, bytes memory returndata) = target.delegatecall(data);
            return verifyCallResult(success, returndata, errorMessage);
        }
        /**
         * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
         * revert reason using the provided one.
         *
         * _Available since v4.3._
         */
        function verifyCallResult(
            bool success,
            bytes memory returndata,
            string memory errorMessage
        ) internal pure returns (bytes memory) {
            if (success) {
                return returndata;
            } else {
                // Look for revert reason and bubble it up if present
                if (returndata.length > 0) {
                    // The easiest way to bubble the revert reason is using memory via assembly
                    assembly {
                        let returndata_size := mload(returndata)
                        revert(add(32, returndata), returndata_size)
                    }
                } else {
                    revert(errorMessage);
                }
            }
        }
    }
    // File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)
    pragma solidity ^0.8.0;
    /**
     * @title ERC721 token receiver interface
     * @dev Interface for any contract that wants to support safeTransfers
     * from ERC721 asset contracts.
     */
    interface IERC721Receiver {
        /**
         * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
         * by `operator` from `from`, this function is called.
         *
         * It must return its Solidity selector to confirm the token transfer.
         * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
         *
         * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
         */
        function onERC721Received(
            address operator,
            address from,
            uint256 tokenId,
            bytes calldata data
        ) external returns (bytes4);
    }
    // File: @openzeppelin/contracts/utils/introspection/IERC165.sol
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Interface of the ERC165 standard, as defined in the
     * https://eips.ethereum.org/EIPS/eip-165[EIP].
     *
     * Implementers can declare support of contract interfaces, which can then be
     * queried by others ({ERC165Checker}).
     *
     * For an implementation, see {ERC165}.
     */
    interface IERC165 {
        /**
         * @dev Returns true if this contract implements the interface defined by
         * `interfaceId`. See the corresponding
         * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
         * to learn more about how these ids are created.
         *
         * This function call must use less than 30 000 gas.
         */
        function supportsInterface(bytes4 interfaceId) external view returns (bool);
    }
    // File: @openzeppelin/contracts/utils/introspection/ERC165.sol
    // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Implementation of the {IERC165} interface.
     *
     * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
     * for the additional interface id that will be supported. For example:
     *
     * ```solidity
     * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
     *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
     * }
     * ```
     *
     * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
     */
    abstract contract ERC165 is IERC165 {
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
            return interfaceId == type(IERC165).interfaceId;
        }
    }
    // File: @openzeppelin/contracts/token/ERC721/IERC721.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Required interface of an ERC721 compliant contract.
     */
    interface IERC721 is IERC165 {
        /**
         * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
         */
        event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
        /**
         * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
         */
        event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
        /**
         * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
         */
        event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
        /**
         * @dev Returns the number of tokens in ``owner``'s account.
         */
        function balanceOf(address owner) external view returns (uint256 balance);
        /**
         * @dev Returns the owner of the `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function ownerOf(uint256 tokenId) external view returns (address owner);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
         * are aware of the ERC721 protocol to prevent tokens from being forever locked.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Transfers `tokenId` token from `from` to `to`.
         *
         * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         *
         * Emits a {Transfer} event.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) external;
        /**
         * @dev Gives permission to `to` to transfer `tokenId` token to another account.
         * The approval is cleared when the token is transferred.
         *
         * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
         *
         * Requirements:
         *
         * - The caller must own the token or be an approved operator.
         * - `tokenId` must exist.
         *
         * Emits an {Approval} event.
         */
        function approve(address to, uint256 tokenId) external;
        /**
         * @dev Returns the account approved for `tokenId` token.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         */
        function getApproved(uint256 tokenId) external view returns (address operator);
        /**
         * @dev Approve or remove `operator` as an operator for the caller.
         * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
         *
         * Requirements:
         *
         * - The `operator` cannot be the caller.
         *
         * Emits an {ApprovalForAll} event.
         */
        function setApprovalForAll(address operator, bool _approved) external;
        /**
         * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
         *
         * See {setApprovalForAll}
         */
        function isApprovedForAll(address owner, address operator) external view returns (bool);
        /**
         * @dev Safely transfers `tokenId` token from `from` to `to`.
         *
         * Requirements:
         *
         * - `from` cannot be the zero address.
         * - `to` cannot be the zero address.
         * - `tokenId` token must exist and be owned by `from`.
         * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
         *
         * Emits a {Transfer} event.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes calldata data
        ) external;
    }
    // File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol
    // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
    pragma solidity ^0.8.0;
    /**
     * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
     * @dev See https://eips.ethereum.org/EIPS/eip-721
     */
    interface IERC721Metadata is IERC721 {
        /**
         * @dev Returns the token collection name.
         */
        function name() external view returns (string memory);
        /**
         * @dev Returns the token collection symbol.
         */
        function symbol() external view returns (string memory);
        /**
         * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
         */
        function tokenURI(uint256 tokenId) external view returns (string memory);
    }
    // File: @openzeppelin/contracts/utils/Context.sol
    // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Provides information about the current execution context, including the
     * sender of the transaction and its data. While these are generally available
     * via msg.sender and msg.data, they should not be accessed in such a direct
     * manner, since when dealing with meta-transactions the account sending and
     * paying for execution may not be the actual sender (as far as an application
     * is concerned).
     *
     * This contract is only required for intermediate, library-like contracts.
     */
    abstract contract Context {
        function _msgSender() internal view virtual returns (address) {
            return msg.sender;
        }
        function _msgData() internal view virtual returns (bytes calldata) {
            return msg.data;
        }
    }
    // File: contracts/erc721a.sol
    // Creator: Chiru Labs
    pragma solidity ^0.8.4;
    error ApprovalCallerNotOwnerNorApproved();
    error ApprovalQueryForNonexistentToken();
    error ApproveToCaller();
    error ApprovalToCurrentOwner();
    error BalanceQueryForZeroAddress();
    error MintToZeroAddress();
    error MintZeroQuantity();
    error OwnerQueryForNonexistentToken();
    error TransferCallerNotOwnerNorApproved();
    error TransferFromIncorrectOwner();
    error TransferToNonERC721ReceiverImplementer();
    error TransferToZeroAddress();
    error URIQueryForNonexistentToken();
    /**
     * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
     * the Metadata extension. Built to optimize for lower gas during batch mints.
     *
     * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
     *
     * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
     *
     * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
     */
    contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
        using Address for address;
        using Strings for uint256;
        // Compiler will pack this into a single 256bit word.
        struct TokenOwnership {
            // The address of the owner.
            address addr;
            // Keeps track of the start time of ownership with minimal overhead for tokenomics.
            uint64 startTimestamp;
            // Whether the token has been burned.
            bool burned;
        }
        // Compiler will pack this into a single 256bit word.
        struct AddressData {
            // Realistically, 2**64-1 is more than enough.
            uint64 balance;
            // Keeps track of mint count with minimal overhead for tokenomics.
            uint64 numberMinted;
            // Keeps track of burn count with minimal overhead for tokenomics.
            uint64 numberBurned;
            // For miscellaneous variable(s) pertaining to the address
            // (e.g. number of whitelist mint slots used).
            // If there are multiple variables, please pack them into a uint64.
            uint64 aux;
        }
        // The tokenId of the next token to be minted.
        uint256 internal _currentIndex;
        // The number of tokens burned.
        uint256 internal _burnCounter;
        // Token name
        string private _name;
        // Token symbol
        string private _symbol;
        // Mapping from token ID to ownership details
        // An empty struct value does not necessarily mean the token is unowned. See _ownershipOf implementation for details.
        mapping(uint256 => TokenOwnership) internal _ownerships;
        // Mapping owner address to address data
        mapping(address => AddressData) private _addressData;
        // Mapping from token ID to approved address
        mapping(uint256 => address) private _tokenApprovals;
        // Mapping from owner to operator approvals
        mapping(address => mapping(address => bool)) private _operatorApprovals;
        constructor(string memory name_, string memory symbol_) {
            _name = name_;
            _symbol = symbol_;
            _currentIndex = _startTokenId();
        }
        /**
         * To change the starting tokenId, please override this function.
         */
        function _startTokenId() internal view virtual returns (uint256) {
            return 1;
        }
        /**
         * @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
         */
        function totalSupply() public view returns (uint256) {
            // Counter underflow is impossible as _burnCounter cannot be incremented
            // more than _currentIndex - _startTokenId() times
            unchecked {
                return _currentIndex - _burnCounter - _startTokenId();
            }
        }
        /**
         * Returns the total amount of tokens minted in the contract.
         */
        function _totalMinted() internal view returns (uint256) {
            // Counter underflow is impossible as _currentIndex does not decrement,
            // and it is initialized to _startTokenId()
            unchecked {
                return _currentIndex - _startTokenId();
            }
        }
        /**
         * @dev See {IERC165-supportsInterface}.
         */
        function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
            return
                interfaceId == type(IERC721).interfaceId ||
                interfaceId == type(IERC721Metadata).interfaceId ||
                super.supportsInterface(interfaceId);
        }
        /**
         * @dev See {IERC721-balanceOf}.
         */
        function balanceOf(address owner) public view override returns (uint256) {
            if (owner == address(0)) revert BalanceQueryForZeroAddress();
            return uint256(_addressData[owner].balance);
        }
        /**
         * Returns the number of tokens minted by `owner`.
         */
        function _numberMinted(address owner) internal view returns (uint256) {
            return uint256(_addressData[owner].numberMinted);
        }
        /**
         * Returns the number of tokens burned by or on behalf of `owner`.
         */
        function _numberBurned(address owner) internal view returns (uint256) {
            return uint256(_addressData[owner].numberBurned);
        }
        /**
         * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
         */
        function _getAux(address owner) internal view returns (uint64) {
            return _addressData[owner].aux;
        }
        /**
         * Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
         * If there are multiple variables, please pack them into a uint64.
         */
        function _setAux(address owner, uint64 aux) internal {
            _addressData[owner].aux = aux;
        }
        /**
         * Gas spent here starts off proportional to the maximum mint batch size.
         * It gradually moves to O(1) as tokens get transferred around in the collection over time.
         */
        function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
            uint256 curr = tokenId;
            unchecked {
                if (_startTokenId() <= curr && curr < _currentIndex) {
                    TokenOwnership memory ownership = _ownerships[curr];
                    if (!ownership.burned) {
                        if (ownership.addr != address(0)) {
                            return ownership;
                        }
                        // Invariant:
                        // There will always be an ownership that has an address and is not burned
                        // before an ownership that does not have an address and is not burned.
                        // Hence, curr will not underflow.
                        while (true) {
                            curr--;
                            ownership = _ownerships[curr];
                            if (ownership.addr != address(0)) {
                                return ownership;
                            }
                        }
                    }
                }
            }
            revert OwnerQueryForNonexistentToken();
        }
        /**
         * @dev See {IERC721-ownerOf}.
         */
        function ownerOf(uint256 tokenId) public view override returns (address) {
            return _ownershipOf(tokenId).addr;
        }
        /**
         * @dev See {IERC721Metadata-name}.
         */
        function name() public view virtual override returns (string memory) {
            return _name;
        }
        /**
         * @dev See {IERC721Metadata-symbol}.
         */
        function symbol() public view virtual override returns (string memory) {
            return _symbol;
        }
        /**
         * @dev See {IERC721Metadata-tokenURI}.
         */
        function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
            if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
            string memory baseURI = _baseURI();
            return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : '';
        }
        /**
         * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
         * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
         * by default, can be overriden in child contracts.
         */
        function _baseURI() internal view virtual returns (string memory) {
            return '';
        }
        /**
         * @dev See {IERC721-approve}.
         */
        function approve(address to, uint256 tokenId) public override {
            address owner = ERC721A.ownerOf(tokenId);
            if (to == owner) revert ApprovalToCurrentOwner();
            if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
                revert ApprovalCallerNotOwnerNorApproved();
            }
            _approve(to, tokenId, owner);
        }
        /**
         * @dev See {IERC721-getApproved}.
         */
        function getApproved(uint256 tokenId) public view override returns (address) {
            if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
            return _tokenApprovals[tokenId];
        }
        /**
         * @dev See {IERC721-setApprovalForAll}.
         */
        function setApprovalForAll(address operator, bool approved) public virtual override {
            if (operator == _msgSender()) revert ApproveToCaller();
            _operatorApprovals[_msgSender()][operator] = approved;
            emit ApprovalForAll(_msgSender(), operator, approved);
        }
        /**
         * @dev See {IERC721-isApprovedForAll}.
         */
        function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
            return _operatorApprovals[owner][operator];
        }
        /**
         * @dev See {IERC721-transferFrom}.
         */
        function transferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            _transfer(from, to, tokenId);
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId
        ) public virtual override {
            safeTransferFrom(from, to, tokenId, '');
        }
        /**
         * @dev See {IERC721-safeTransferFrom}.
         */
        function safeTransferFrom(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) public virtual override {
            _transfer(from, to, tokenId);
            if (to.isContract() && !_checkContractOnERC721Received(from, to, tokenId, _data)) {
                revert TransferToNonERC721ReceiverImplementer();
            }
        }
        /**
         * @dev Returns whether `tokenId` exists.
         *
         * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
         *
         * Tokens start existing when they are minted (`_mint`),
         */
        function _exists(uint256 tokenId) internal view returns (bool) {
            return _startTokenId() <= tokenId && tokenId < _currentIndex &&
                !_ownerships[tokenId].burned;
        }
        function _safeMint(address to, uint256 quantity) internal {
            _safeMint(to, quantity, '');
        }
        /**
         * @dev Safely mints `quantity` tokens and transfers them to `to`.
         *
         * Requirements:
         *
         * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
         * - `quantity` must be greater than 0.
         *
         * Emits a {Transfer} event.
         */
        function _safeMint(
            address to,
            uint256 quantity,
            bytes memory _data
        ) internal {
            _mint(to, quantity, _data, true);
        }
        /**
         * @dev Mints `quantity` tokens and transfers them to `to`.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `quantity` must be greater than 0.
         *
         * Emits a {Transfer} event.
         */
        function _mint(
            address to,
            uint256 quantity,
            bytes memory _data,
            bool safe
        ) internal {
            uint256 startTokenId = _currentIndex;
            if (to == address(0)) revert MintToZeroAddress();
            if (quantity == 0) revert MintZeroQuantity();
            _beforeTokenTransfers(address(0), to, startTokenId, quantity);
            // Overflows are incredibly unrealistic.
            // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
            // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
            unchecked {
                _addressData[to].balance += uint64(quantity);
                _addressData[to].numberMinted += uint64(quantity);
                _ownerships[startTokenId].addr = to;
                _ownerships[startTokenId].startTimestamp = uint64(block.timestamp);
                uint256 updatedIndex = startTokenId;
                uint256 end = updatedIndex + quantity;
                if (safe && to.isContract()) {
                    do {
                        emit Transfer(address(0), to, updatedIndex);
                        if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
                            revert TransferToNonERC721ReceiverImplementer();
                        }
                    } while (updatedIndex != end);
                    // Reentrancy protection
                    if (_currentIndex != startTokenId) revert();
                } else {
                    do {
                        emit Transfer(address(0), to, updatedIndex++);
                    } while (updatedIndex != end);
                }
                _currentIndex = updatedIndex;
            }
            _afterTokenTransfers(address(0), to, startTokenId, quantity);
        }
        /**
         * @dev Transfers `tokenId` from `from` to `to`.
         *
         * Requirements:
         *
         * - `to` cannot be the zero address.
         * - `tokenId` token must be owned by `from`.
         *
         * Emits a {Transfer} event.
         */
        function _transfer(
            address from,
            address to,
            uint256 tokenId
        ) private {
            TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
            if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
            bool isApprovedOrOwner = (_msgSender() == from ||
                isApprovedForAll(from, _msgSender()) ||
                getApproved(tokenId) == _msgSender());
            if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
            if (to == address(0)) revert TransferToZeroAddress();
            _beforeTokenTransfers(from, to, tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, from);
            // Underflow of the sender's balance is impossible because we check for
            // ownership above and the recipient's balance can't realistically overflow.
            // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
            unchecked {
                _addressData[from].balance -= 1;
                _addressData[to].balance += 1;
                TokenOwnership storage currSlot = _ownerships[tokenId];
                currSlot.addr = to;
                currSlot.startTimestamp = uint64(block.timestamp);
                // If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
                // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
                uint256 nextTokenId = tokenId + 1;
                TokenOwnership storage nextSlot = _ownerships[nextTokenId];
                if (nextSlot.addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId != _currentIndex) {
                        nextSlot.addr = from;
                        nextSlot.startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(from, to, tokenId);
            _afterTokenTransfers(from, to, tokenId, 1);
        }
        /**
         * @dev This is equivalent to _burn(tokenId, false)
         */
        function _burn(uint256 tokenId) internal virtual {
            _burn(tokenId, false);
        }
        /**
         * @dev Destroys `tokenId`.
         * The approval is cleared when the token is burned.
         *
         * Requirements:
         *
         * - `tokenId` must exist.
         *
         * Emits a {Transfer} event.
         */
        function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
            TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
            address from = prevOwnership.addr;
            if (approvalCheck) {
                bool isApprovedOrOwner = (_msgSender() == from ||
                    isApprovedForAll(from, _msgSender()) ||
                    getApproved(tokenId) == _msgSender());
                if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
            }
            _beforeTokenTransfers(from, address(0), tokenId, 1);
            // Clear approvals from the previous owner
            _approve(address(0), tokenId, from);
            // Underflow of the sender's balance is impossible because we check for
            // ownership above and the recipient's balance can't realistically overflow.
            // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
            unchecked {
                AddressData storage addressData = _addressData[from];
                addressData.balance -= 1;
                addressData.numberBurned += 1;
                // Keep track of who burned the token, and the timestamp of burning.
                TokenOwnership storage currSlot = _ownerships[tokenId];
                currSlot.addr = from;
                currSlot.startTimestamp = uint64(block.timestamp);
                currSlot.burned = true;
                // If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
                // Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
                uint256 nextTokenId = tokenId + 1;
                TokenOwnership storage nextSlot = _ownerships[nextTokenId];
                if (nextSlot.addr == address(0)) {
                    // This will suffice for checking _exists(nextTokenId),
                    // as a burned slot cannot contain the zero address.
                    if (nextTokenId != _currentIndex) {
                        nextSlot.addr = from;
                        nextSlot.startTimestamp = prevOwnership.startTimestamp;
                    }
                }
            }
            emit Transfer(from, address(0), tokenId);
            _afterTokenTransfers(from, address(0), tokenId, 1);
            // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
            unchecked {
                _burnCounter++;
            }
        }
        /**
         * @dev Approve `to` to operate on `tokenId`
         *
         * Emits a {Approval} event.
         */
        function _approve(
            address to,
            uint256 tokenId,
            address owner
        ) private {
            _tokenApprovals[tokenId] = to;
            emit Approval(owner, to, tokenId);
        }
        /**
         * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
         *
         * @param from address representing the previous owner of the given token ID
         * @param to target address that will receive the tokens
         * @param tokenId uint256 ID of the token to be transferred
         * @param _data bytes optional data to send along with the call
         * @return bool whether the call correctly returned the expected magic value
         */
        function _checkContractOnERC721Received(
            address from,
            address to,
            uint256 tokenId,
            bytes memory _data
        ) private returns (bool) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                return retval == IERC721Receiver(to).onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert TransferToNonERC721ReceiverImplementer();
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        }
        /**
         * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
         * And also called before burning one token.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
         * transferred to `to`.
         * - When `from` is zero, `tokenId` will be minted for `to`.
         * - When `to` is zero, `tokenId` will be burned by `from`.
         * - `from` and `to` are never both zero.
         */
        function _beforeTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
        /**
         * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
         * minting.
         * And also called after one token has been burned.
         *
         * startTokenId - the first token id to be transferred
         * quantity - the amount to be transferred
         *
         * Calling conditions:
         *
         * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
         * transferred to `to`.
         * - When `from` is zero, `tokenId` has been minted for `to`.
         * - When `to` is zero, `tokenId` has been burned by `from`.
         * - `from` and `to` are never both zero.
         */
        function _afterTokenTransfers(
            address from,
            address to,
            uint256 startTokenId,
            uint256 quantity
        ) internal virtual {}
    }
    // File: @openzeppelin/contracts/access/Ownable.sol
    // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
    pragma solidity ^0.8.0;
    /**
     * @dev Contract module which provides a basic access control mechanism, where
     * there is an account (an owner) that can be granted exclusive access to
     * specific functions.
     *
     * By default, the owner account will be the one that deploys the contract. This
     * can later be changed with {transferOwnership}.
     *
     * This module is used through inheritance. It will make available the modifier
     * `onlyOwner`, which can be applied to your functions to restrict their use to
     * the owner.
     */
    abstract contract Ownable is Context {
        address private _owner;
        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
        /**
         * @dev Initializes the contract setting the deployer as the initial owner.
         */
        constructor() {
            _transferOwnership(_msgSender());
        }
        /**
         * @dev Returns the address of the current owner.
         */
        function owner() public view virtual returns (address) {
            return _owner;
        }
        /**
         * @dev Throws if called by any account other than the owner.
         */
        modifier onlyOwner() {
            require(owner() == _msgSender(), "Ownable: caller is not the owner");
            _;
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Can only be called by the current owner.
         */
        function transferOwnership(address newOwner) public virtual onlyOwner {
            require(newOwner != address(0), "Ownable: new owner is the zero address");
            _transferOwnership(newOwner);
        }
        /**
         * @dev Transfers ownership of the contract to a new account (`newOwner`).
         * Internal function without access restriction.
         */
        function _transferOwnership(address newOwner) internal virtual {
            address oldOwner = _owner;
            _owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }
    // File: openzeppelin-contracts/blob/master/contracts/token/ERC721/extensions/ERC721Burnable.sol
    // SPDX-License-Identifier: MIT
    // Creator: Chiru Labs
    pragma solidity ^0.8.4;
    /**
     * @title ERC721A Burnable Token
     * @dev ERC721A Token that can be irreversibly burned (destroyed).
     */
    abstract contract ERC721ABurnable is ERC721A {
        /**
         * @dev Burns `tokenId`. See {ERC721A-_burn}.
         *
         * Requirements:
         *
         * - The caller must own `tokenId` or be an approved operator.
         */
        function burn(uint256 tokenId) public virtual {
            _burn(tokenId, true);
        }
    }
    // File: contracts/contract.sol
    pragma solidity ^0.8.4;
    contract BITRING is Ownable, ERC721A, DefaultOperatorFilterer, ERC721ABurnable  {
        using Strings for uint256;
        string private baseTokenURI;
        uint256 public presaleCost = 0.05 ether;
        uint256 public publicSaleCost = 0.1 ether;
        uint64 public maxSupply = 1000;
        bool public presaleActive = false;
        bool public publicSaleActive = false;
        constructor() ERC721A("BITRING", "BITRING"){}
        modifier mintCompliance(uint256 _mintAmount) {
            require(_mintAmount > 0 , "Invalid mint amount!");
            require(totalMinted() + _mintAmount <= maxSupply, "Max supply exceeded!");
            _;
        }
        ///Mints NFTs for whitelist members during the presale
        function presaleMint(uint64 _mintAmount) public payable mintCompliance(_mintAmount) {
            require(presaleActive, "Presale is not Active");
            _safeMint(msg.sender, _mintAmount);
        }
        ///Allows any address to mint when the public sale is open
        function publicMint(uint64 _mintAmount) public payable mintCompliance(_mintAmount) {
            require(publicSaleActive, "Public is not Active");
            require(tx.origin == msg.sender);
            require(msg.value == publicSaleCost * _mintAmount, "Insufficient funds!");
            _safeMint(msg.sender, _mintAmount);
        }
        ///Allows owner of the collection to airdrop a token to any address
        function ownerMint(uint256 _mintAmount, address _receiver) public mintCompliance(_mintAmount) onlyOwner {
            _safeMint(_receiver, _mintAmount);
        }
        //@return token ids owned by an address in the collection
        function walletOfOwner(address _owner)
            external
            view
            returns (uint256[] memory)
        {
            uint256 ownerTokenCount = balanceOf(_owner);
            uint256[] memory ownedTokenIds = new uint256[](ownerTokenCount);
            uint256 currentTokenId = 1;
            uint256 ownedTokenIndex = 0;
            while (ownedTokenIndex < ownerTokenCount && currentTokenId <= maxSupply) {
                if(exists(currentTokenId) == true) {
                    address currentTokenOwner = ownerOf(currentTokenId);
                    if (currentTokenOwner == _owner) {
                        ownedTokenIds[ownedTokenIndex] = currentTokenId;
                        ownedTokenIndex++;
                    }
                }
                currentTokenId++;
            }
            return ownedTokenIds;
        }
        function setPubCost(uint256 _newCost) public onlyOwner {
            publicSaleCost = _newCost;
        }
        function transferFrom(address from, address to, uint256 tokenId) public override onlyAllowedOperator(from) {
            super.transferFrom(from, to, tokenId);
        }
        function safeTransferFrom(address from, address to, uint256 tokenId) public override onlyAllowedOperator(from) {
            super.safeTransferFrom(from, to, tokenId);
        }
        function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data)
            public
            override
            onlyAllowedOperator(from)
        {
            super.safeTransferFrom(from, to, tokenId, data);
        }
        //@return full url for passed in token id 
        function tokenURI(uint256 _tokenId)
            public
            view
            virtual
            override
            returns (string memory)
        {
            require(
            _exists(_tokenId),
            "ERC721Metadata: URI query for nonexistent token"
            );
            string memory currentBaseURI = _baseURI();
            return bytes(currentBaseURI).length > 0
                ? string(abi.encodePacked(currentBaseURI, _tokenId.toString(), ".json"))
                : "";
        }
        //@return all NFT's minted including burned tokens
        function totalMinted() public view returns (uint256) {
            return _totalMinted();
        }
        function exists(uint256 _tokenId) public view returns (bool) {
            return _exists(_tokenId);
        }
        //@return url for the nft metadata
        function _baseURI() internal view virtual override returns (string memory) {
            return baseTokenURI;
        }
        function setBaseURI(string calldata _URI) external onlyOwner {
            baseTokenURI = _URI;
        }
        
        function setPresaleActive(bool _state) public onlyOwner {
            presaleActive = _state;
        }
        function setPublicActive(bool _state) public onlyOwner {
            publicSaleActive = _state;
        }
        function withdraw() public onlyOwner {
            (bool os, ) = payable(owner()).call{value: address(this).balance}("");
            require(os);
        }
        /// Fallbacks 
        receive() external payable { }
        fallback() external payable { }
    }