ETH Price: $2,439.21 (-1.52%)

Transaction Decoder

Block:
15761800 at Oct-16-2022 04:14:23 PM +UTC
Transaction Fee:
0.001572945622998932 ETH $3.84
Gas Used:
101,491 Gas / 15.498375452 Gwei

Emitted Events:

241 WoWGalaxy.Approval( owner=0x91aa9D9F...9e0123a00, approved=0x00000000...000000000, tokenId=1721 )
242 WoWGalaxy.Transfer( from=0x91aa9D9F...9e0123a00, to=0x448891c1...983bF48CF, tokenId=1721 )

Account State Difference:

  Address   Before After State Difference Code
0x4353450e...F44e169e5
0.154391983284155643 Eth
Nonce: 361
0.152819037661156711 Eth
Nonce: 362
0.001572945622998932
(builder0x69)
0.770272140116339124 Eth0.770576613116339124 Eth0.000304473
0xf61F24c2...31F28d6dC

Execution Trace

Fake_Phishing6990.2d8bf0c5( )
  • 0xce0f0395dd9f9aabc725d1f0654f09489d508988.2d8bf0c5( )
    • WoWGalaxy.safeTransferFrom( from=0x91aa9D9F227d891c12350d97C20dc6A9e0123a00, to=0x448891c149A699264Daa8b9b290d2B5983bF48CF, tokenId=1721, _data=0x )
      // SPDX-License-Identifier: MIT
      pragma solidity ^0.8.11;
      import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
      import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
      import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
      import "@openzeppelin/contracts/access/Ownable.sol";
      import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
      import "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
      import "@openzeppelin/contracts/token/common/ERC2981.sol";
      //
      //
      //
      //                                   ,#((((((((
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      //      @@&@&&&&&&&&&&&&&&&&&&&&.%&&&&&&,     @&&&&&&  &&&&&&&&&&&&&&&&&&&&&@@(
      //       &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&    @&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
      //       @&&&&&&&&&&&&&&&&@@@&&&&&&&&&&&&&   &&&&&&&&&&&&&@@&&&&&&&&&&&&&&&&&
      //        &&&&&&&&&&&&&&&@@@@@&&&&&&&&&&&&@.@&&&&&&&&&&&&@@@@&&&&&&&&&&&&&&&&
      //         &&&&&&&&&&&&&@&&&&&&&&&&&&&&&###(/##&&&&&&&&&&&&&&&&&&&&&&&&&&&&&
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      //              @@&&&&&&&&&@@&&&&&&@@@@@##((/#%@@@@&&&&&&@@&&&&&&&&&&@@
      /**
       * @title WoWGalaxy Contract
       * @author Ben Yu, Itzik Lerner, @RMinLA, Mai Akiyoshi, Morgan Giraud, Toomaie, Eugene Strelkov
       * @notice This contract handles minting and distribution of World of Women Galaxy tokens.
       */
      contract WoWGalaxy is ERC721, ERC721Enumerable, ERC2981, ReentrancyGuard, Ownable {
          using ECDSA for bytes32;
          using Strings for uint256;
          uint256 constant TOTAL_FREE_CLAIM_IDS = 10000;
          uint256 constant FIRST_PUBLIC_ID      = 10000;
          uint256 constant LAST_PUBLIC_ID       = 19999;
          uint256 constant FIRST_ALLOWLIST_ID   = 20000;
          uint256 constant LAST_ALLOWLIST_ID    = 22221;
          uint256 constant MAX_MINTS_PER_TRANSACTION = 20;
          address constant WOW_CONTRACT_ADDRESS = 0xe785E82358879F061BC3dcAC6f0444462D4b5330;
          address constant WITHDRAW_ADDRESS = 0x646B9Ed09B130899be4c4bEc114A1aA94618bE09;
          address public royaltyAddress = 0x646B9Ed09B130899be4c4bEc114A1aA94618bE09;
          uint96 public royaltyFee = 400;
          // Public vars
          string public wowGProvenance;
          uint256 public wowGProvenanceTimestamp;
          string public baseTokenURI;
          uint256 public allowListPrice;
          uint256 public dutchAuctionDuration;
          uint256[] public dutchAuctionSteps;
          uint256 private minutesPerStep;
          uint256 public freeClaimSaleStartTime;
          uint256 public publicSaleStartTime;
          uint256 public allowListSaleStartTime;
          bytes32 public merkleRoot;
          uint256 public startingIndexFreeClaim;
          uint256 public startingIndexFreeClaimTimestamp;
          uint256 public startingIndexPublicAndAllowList;
          uint256 public startingIndexPublicAndAllowListTimestamp;
          mapping(address => bool) public allowListMinted;
          uint256 public freeClaimTokensMinted;
          uint256 public allowListTokenIdCounter = FIRST_ALLOWLIST_ID;
          uint256 public publicSaleTokenIdCounter = FIRST_PUBLIC_ID;
          bool public isFreeClaimActive = false;
          bool public isPublicSaleActive = false;
          bool public isAllowListActive = false;
          // support eth transactions to the contract
          event Received(address, uint);
          receive() external payable {
              emit Received(msg.sender, msg.value);
          }
          /**
           * @notice Construct a WoWG contract instance
           * @param _name Token name
           * @param _symbol Token symbol
           * @param _baseTokenURI Base URI for all tokens
           */
          constructor(
              string memory _name,
              string memory _symbol,
              string memory _baseTokenURI
          ) ERC721(_name, _symbol) {
              baseTokenURI = _baseTokenURI;
              _setDefaultRoyalty(royaltyAddress, royaltyFee);
          }
          modifier originalUser() {
              require(msg.sender == tx.origin,"MUST_INVOKE_FUNCTION_DIRECTLY");
              _;
          }
          /**
           * @notice Update the base token URI
           */
          function setBaseURI(string calldata _newBaseURI) external onlyOwner {
              baseTokenURI = _newBaseURI;
          }
          /**
           * @notice read the base token URI
           */
          function _baseURI() internal view override returns (string memory) {
              return baseTokenURI;
          }
          /**
           * @notice Change the royalty fee for the collection
           */
          function setRoyaltyFee(uint96 _feeNumerator) external onlyOwner {
              royaltyFee = _feeNumerator;
              _setDefaultRoyalty(royaltyAddress, royaltyFee);
          }
          /**
           * @notice Change the royalty address where royalty payouts are sent
           */
          function setRoyaltyAddress(address _royaltyAddress) external onlyOwner {
              royaltyAddress = _royaltyAddress;
              _setDefaultRoyalty(royaltyAddress, royaltyFee);
          }
          /**
           * @notice Sets a provenance hash of pregenerated tokens for fairness. Should be set before first token mints
           */
          function setProvenanceHash(string memory _provenanceHash) public onlyOwner {
              wowGProvenance = _provenanceHash;
              wowGProvenanceTimestamp = block.timestamp;
          }
          /**
           * @notice Manually allow the owner to set the starting index for the free claim mint
           */
          function setStartingIndexFreeClaim() external onlyOwner {
              _setStartingIndexFreeClaim();
          }
          /**
           * @notice Set the starting index for the free claim mint
           */
          function _setStartingIndexFreeClaim() internal {
              require(startingIndexFreeClaim == 0, "STARTING_INDEX_FREE_CLAIM_ALREADY_SET");
              startingIndexFreeClaim = generateRandomStartingIndex(TOTAL_FREE_CLAIM_IDS);
              startingIndexFreeClaimTimestamp = block.timestamp;
          }
          /**
           * @notice Manually allow the owner to set the starting index for the public and allow list mints
           */
          function setStartingIndexPublicAndAllowList() external onlyOwner {
              _setStartingIndexPublicAndAllowList();
          }
          /**
           * @notice Set the starting index for the public and allow list mints
           */
          function _setStartingIndexPublicAndAllowList() internal {
              require(startingIndexPublicAndAllowList == 0, "STARTING_INDEX_PUBLIC_AND_ALLOWLIST_ALREADY_SET");
              startingIndexPublicAndAllowList = generateRandomStartingIndex(
                  LAST_ALLOWLIST_ID - FIRST_ALLOWLIST_ID + 1 +
                  LAST_PUBLIC_ID - FIRST_PUBLIC_ID + 1);
              startingIndexPublicAndAllowListTimestamp = block.timestamp;
          }
          /**
           * @notice Creates a random starting index to offset pregenerated tokens by for fairness
           */
          function generateRandomStartingIndex(uint256  _range) public view returns (uint256) {
              uint256 startingIndex;
              // Blockhash only works for the most 256 recent blocks.
              uint256 _block_shift = uint(keccak256(abi.encodePacked(block.difficulty, block.timestamp)));
              _block_shift =  1 + (_block_shift % 255);
              // This shouldn't happen, but just in case the blockchain gets a reboot?
              if (block.number < _block_shift) {
                  _block_shift = 1;
              }
              uint256 _block_ref = block.number - _block_shift;
              startingIndex = uint(blockhash(_block_ref)) % _range;
              // Prevent default sequence
              if (startingIndex == 0) {
                  startingIndex++;
              }
              return startingIndex;
          }
          /**
           * @notice Set the steps and duration in minutes for the public Dutch auction mint
           */
          function setDutchAuctionParams(uint256[] calldata _steps, uint256 _duration)
              public
              onlyOwner
          {
              require(_steps.length > 0 && _duration > 0,'ZERO_STEPS_OR_ZERO_DURATION');
              dutchAuctionSteps = _steps;
              dutchAuctionDuration = _duration;
              minutesPerStep = dutchAuctionDuration / dutchAuctionSteps.length;
          }
          /**
           * @notice Retrieve the current Dutch auction price per token
           */
          function getCurrentDutchAuctionPrice() public view returns (uint256) {
              uint256 minutesPassed =
                  uint256(block.timestamp - publicSaleStartTime) / 60;
              if (minutesPassed >= dutchAuctionDuration) {
                  return dutchAuctionSteps[dutchAuctionSteps.length - 1];
              }
              return dutchAuctionSteps[minutesPassed / minutesPerStep];
          }
          /**
           * @notice Set the price per token for the allow list mint
           */
          function setAllowListPrice(uint256 _newAllowListPrice) public onlyOwner {
              require(_newAllowListPrice > 0 ether, "CANT_SET_ALLOW_LIST_PRICE_BACK_TO_ZERO");
              allowListPrice = _newAllowListPrice;
          }
          /**
           * @notice Set the merkle root for the allow list mint
           */
          function setMerkleRoot(bytes32 _merkleRoot) external onlyOwner {
              merkleRoot = _merkleRoot;
          }
          /**
           * @notice Verify address eligibility for the allow list mint
           */
          function isAllowListEligible(address addr, bytes32[] calldata _merkleProof) public view returns (bool) {
              bytes32 leaf = keccak256(abi.encodePacked(addr));
              return MerkleProof.verify(_merkleProof, merkleRoot, leaf);
          }
          // Sales
          /**
           * @notice Set the active/inactive state of the allow list mint
           */
          function flipAllowListState() public onlyOwner {
              require(isAllowListActive || allowListPrice > 0, "ALLOW_LIST_PRICE_NOT_SET");
              isAllowListActive = !isAllowListActive;
              if (allowListSaleStartTime == 0) {
                  allowListSaleStartTime = block.timestamp;
              }
          }
          /**
           * @notice Allow an address on the allow list to mint a single token
           */
          function allowListMint(bytes32[] calldata _merkleProof)
              external
              payable
              nonReentrant
              originalUser
          {
              require(isAllowListActive, "ALLOW_LIST_SALE_IS_NOT_ACTIVE");
              require(allowListTokenIdCounter <= LAST_ALLOWLIST_ID, "INSUFFICIENT_SUPPLY");
              require(
                  !allowListMinted[msg.sender],
                  "ADDRESS_ALREADY_MINTED_IN_ALLOW_LIST"
              );
              bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
              require(
                  MerkleProof.verify(_merkleProof, merkleRoot, leaf),
                  "ADDRESS_NOT_ELIGIBLE_FOR_ALLOW_LIST"
              );
              require(msg.value == allowListPrice, "INVALID_PRICE");
              allowListMinted[msg.sender] = true;
              _safeMint(msg.sender, allowListTokenIdCounter);
              allowListTokenIdCounter++;
          }
          /**
           * @notice Allow the owner to start/stop the public sale
           */
          function flipPublicSaleState() public onlyOwner {
              isPublicSaleActive = !isPublicSaleActive;
              if (publicSaleStartTime == 0) {
                  publicSaleStartTime = block.timestamp;
              } else {
                  publicSaleStartTime = 0;
              }
          }
          /**
           * @notice Allow anyone to mint tokens publicly
           */
          function publicSaleMint(uint256 _numberToMint)
              external
              payable
              nonReentrant
              originalUser
          {
              require(isPublicSaleActive, "PUBLIC_SALE_IS_NOT_ACTIVE");
              uint256 costToMint = getCurrentDutchAuctionPrice() * _numberToMint;
              require(
                  _numberToMint <= MAX_MINTS_PER_TRANSACTION,
                  "EXCEEDS_MAX_MINTS_PER_TRANSACTION"
              );
              require(
                  msg.value >= costToMint,
                  "INSUFFICIENT_PAYMENT"
              );
              require(
                  publicSaleTokenIdCounter + _numberToMint <= LAST_PUBLIC_ID + 1,
                  "INSUFFICIENT_SUPPLY"
              );
              for (uint256 i; i < _numberToMint; i++) {
                  _safeMint(msg.sender, publicSaleTokenIdCounter + i);
              }
              publicSaleTokenIdCounter += _numberToMint;
              // last mint will increase the counter past LAST_PUBLIC_ID
              if (publicSaleTokenIdCounter > LAST_PUBLIC_ID) {
                  isPublicSaleActive = false;
                  if (startingIndexPublicAndAllowList == 0) {
                      _setStartingIndexPublicAndAllowList();
                  }
              }
              if (msg.value > costToMint) {
                  Address.sendValue(payable(msg.sender), msg.value - costToMint);
              }
          }
          /**
           * @notice Allow to owner to start/stop the free claim mint
           */
          function flipFreeClaimState() public onlyOwner {
              isFreeClaimActive = !isFreeClaimActive;
              if (freeClaimSaleStartTime == 0) {
                  freeClaimSaleStartTime = block.timestamp;
              }
          }
          /**
           * @notice Allow an existing WoW holder to mint corresponding WoWG tokens for free
           */
          function freeClaimMint(uint256[] calldata _tokenIDs)
              external
              nonReentrant
          {
              require(isFreeClaimActive, "FREE_CLAIM_IS_NOT_ACTIVE");
              uint256 numberToMint = _tokenIDs.length;
              require(
                  numberToMint <= MAX_MINTS_PER_TRANSACTION,
                  "EXCEEDS_MAX_MINTS_PER_TRANSACTION"
              );
              ERC721 WoW = ERC721(WOW_CONTRACT_ADDRESS);
              for (uint256 i; i < numberToMint; i++) {
                  require(WoW.ownerOf(_tokenIDs[i]) == msg.sender, "DOES_NOT_OWN_WOW_TOKEN_ID");
                  _safeMint(msg.sender, _tokenIDs[i]);
                  freeClaimTokensMinted++;
              }
              if (freeClaimTokensMinted == TOTAL_FREE_CLAIM_IDS) {
                  isFreeClaimActive = false;
              }
              // set starting index for free claim tokens as soon as the first token is minted
              if (startingIndexFreeClaim == 0) {
                  _setStartingIndexFreeClaim();
              }
          }
          /**
           * @notice Easily get the number of steps for the public sale
           */
          function getDutchAuctionStepsCount() public view returns (uint256 count) {
              return dutchAuctionSteps.length;
          }
          // Owner
          /**
           * @notice Allow the owner to gift tokens to an arbitrary number of addresses
           */
          function giftMint(address[] calldata _receivers) external onlyOwner {
              require(
                  allowListTokenIdCounter + _receivers.length <= LAST_ALLOWLIST_ID + 1,
                  "NOT_ENOUGH_ALLOW_LIST_TOKENS_REMAINING"
              );
              for (uint256 i; i < _receivers.length; i++) {
                  _safeMint(_receivers[i], allowListTokenIdCounter + i);
              }
              allowListTokenIdCounter += _receivers.length;
          }
          /**
           * @notice Allow withdrawing funds to the withdrawAddress
           */
          function withdraw() public onlyOwner {
              uint256 balance = address(this).balance;
              require(balance > 0,'NOTHING_TO_WITHDRAW');
              require(payable(WITHDRAW_ADDRESS).send(balance));
          }
          // Utils
          /**
           * @notice Returns a list of token IDs owned by a given address
           */
          function walletOfOwner(address _owner) public view returns(uint256[] memory) {
              uint256 tokenCount = balanceOf(_owner);
              uint256[] memory tokensId = new uint256[](tokenCount);
              for(uint256 i; i < tokenCount; i++){
                  tokensId[i] = tokenOfOwnerByIndex(_owner, i);
              }
              return tokensId;
          }
          /**
           * @notice Allow external checks for token existence
           */
          function tokenExists(uint256 _tokenId) public view returns(bool) {
              return _exists(_tokenId);
          }
          function supportsInterface(bytes4 interfaceId)
              public
              view
              override(ERC721, ERC721Enumerable, ERC2981)
              returns (bool)
          {
              return super.supportsInterface(interfaceId);
          }
          function _beforeTokenTransfer(address from, address to, uint256 tokenId)
              internal
              override(ERC721, ERC721Enumerable)
          {
              super._beforeTokenTransfer(from, to, tokenId);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/ERC721.sol)
      pragma solidity ^0.8.0;
      import "./IERC721.sol";
      import "./IERC721Receiver.sol";
      import "./extensions/IERC721Metadata.sol";
      import "../../utils/Address.sol";
      import "../../utils/Context.sol";
      import "../../utils/Strings.sol";
      import "../../utils/introspection/ERC165.sol";
      /**
       * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
       * the Metadata extension, but not including the Enumerable extension, which is available separately as
       * {ERC721Enumerable}.
       */
      contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
          using Address for address;
          using Strings for uint256;
          // Token name
          string private _name;
          // Token symbol
          string private _symbol;
          // Mapping from token ID to owner address
          mapping(uint256 => address) private _owners;
          // Mapping owner address to token count
          mapping(address => uint256) private _balances;
          // 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;
          /**
           * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
           */
          constructor(string memory name_, string memory symbol_) {
              _name = name_;
              _symbol = symbol_;
          }
          /**
           * @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 virtual override returns (uint256) {
              require(owner != address(0), "ERC721: balance query for the zero address");
              return _balances[owner];
          }
          /**
           * @dev See {IERC721-ownerOf}.
           */
          function ownerOf(uint256 tokenId) public view virtual override returns (address) {
              address owner = _owners[tokenId];
              require(owner != address(0), "ERC721: owner query for nonexistent token");
              return owner;
          }
          /**
           * @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) {
              require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
              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 virtual override {
              address owner = ERC721.ownerOf(tokenId);
              require(to != owner, "ERC721: approval to current owner");
              require(
                  _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
                  "ERC721: approve caller is not owner nor approved for all"
              );
              _approve(to, tokenId);
          }
          /**
           * @dev See {IERC721-getApproved}.
           */
          function getApproved(uint256 tokenId) public view virtual override returns (address) {
              require(_exists(tokenId), "ERC721: approved query for nonexistent token");
              return _tokenApprovals[tokenId];
          }
          /**
           * @dev See {IERC721-setApprovalForAll}.
           */
          function setApprovalForAll(address operator, bool approved) public virtual override {
              _setApprovalForAll(_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 {
              //solhint-disable-next-line max-line-length
              require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
              _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 {
              require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
              _safeTransfer(from, to, tokenId, _data);
          }
          /**
           * @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.
           *
           * `_data` is additional data, it has no specified format and it is sent in call to `to`.
           *
           * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
           * implement alternative mechanisms to perform token transfer, such as signature-based.
           *
           * Requirements:
           *
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           * - `tokenId` token must exist and be owned by `from`.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function _safeTransfer(
              address from,
              address to,
              uint256 tokenId,
              bytes memory _data
          ) internal virtual {
              _transfer(from, to, tokenId);
              require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
          }
          /**
           * @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`),
           * and stop existing when they are burned (`_burn`).
           */
          function _exists(uint256 tokenId) internal view virtual returns (bool) {
              return _owners[tokenId] != address(0);
          }
          /**
           * @dev Returns whether `spender` is allowed to manage `tokenId`.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           */
          function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
              require(_exists(tokenId), "ERC721: operator query for nonexistent token");
              address owner = ERC721.ownerOf(tokenId);
              return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
          }
          /**
           * @dev Safely mints `tokenId` and transfers it to `to`.
           *
           * Requirements:
           *
           * - `tokenId` must not exist.
           * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
           *
           * Emits a {Transfer} event.
           */
          function _safeMint(address to, uint256 tokenId) internal virtual {
              _safeMint(to, tokenId, "");
          }
          /**
           * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
           * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
           */
          function _safeMint(
              address to,
              uint256 tokenId,
              bytes memory _data
          ) internal virtual {
              _mint(to, tokenId);
              require(
                  _checkOnERC721Received(address(0), to, tokenId, _data),
                  "ERC721: transfer to non ERC721Receiver implementer"
              );
          }
          /**
           * @dev Mints `tokenId` and transfers it to `to`.
           *
           * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
           *
           * Requirements:
           *
           * - `tokenId` must not exist.
           * - `to` cannot be the zero address.
           *
           * Emits a {Transfer} event.
           */
          function _mint(address to, uint256 tokenId) internal virtual {
              require(to != address(0), "ERC721: mint to the zero address");
              require(!_exists(tokenId), "ERC721: token already minted");
              _beforeTokenTransfer(address(0), to, tokenId);
              _balances[to] += 1;
              _owners[tokenId] = to;
              emit Transfer(address(0), to, tokenId);
              _afterTokenTransfer(address(0), to, tokenId);
          }
          /**
           * @dev Destroys `tokenId`.
           * The approval is cleared when the token is burned.
           *
           * Requirements:
           *
           * - `tokenId` must exist.
           *
           * Emits a {Transfer} event.
           */
          function _burn(uint256 tokenId) internal virtual {
              address owner = ERC721.ownerOf(tokenId);
              _beforeTokenTransfer(owner, address(0), tokenId);
              // Clear approvals
              _approve(address(0), tokenId);
              _balances[owner] -= 1;
              delete _owners[tokenId];
              emit Transfer(owner, address(0), tokenId);
              _afterTokenTransfer(owner, address(0), tokenId);
          }
          /**
           * @dev Transfers `tokenId` from `from` to `to`.
           *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
           *
           * 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
          ) internal virtual {
              require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
              require(to != address(0), "ERC721: transfer to the zero address");
              _beforeTokenTransfer(from, to, tokenId);
              // Clear approvals from the previous owner
              _approve(address(0), tokenId);
              _balances[from] -= 1;
              _balances[to] += 1;
              _owners[tokenId] = to;
              emit Transfer(from, to, tokenId);
              _afterTokenTransfer(from, to, tokenId);
          }
          /**
           * @dev Approve `to` to operate on `tokenId`
           *
           * Emits a {Approval} event.
           */
          function _approve(address to, uint256 tokenId) internal virtual {
              _tokenApprovals[tokenId] = to;
              emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
          }
          /**
           * @dev Approve `operator` to operate on all of `owner` tokens
           *
           * Emits a {ApprovalForAll} event.
           */
          function _setApprovalForAll(
              address owner,
              address operator,
              bool approved
          ) internal virtual {
              require(owner != operator, "ERC721: approve to caller");
              _operatorApprovals[owner][operator] = approved;
              emit ApprovalForAll(owner, operator, approved);
          }
          /**
           * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
           * The call is not executed if the target address is not a 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 _checkOnERC721Received(
              address from,
              address to,
              uint256 tokenId,
              bytes memory _data
          ) private returns (bool) {
              if (to.isContract()) {
                  try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
                      return retval == IERC721Receiver.onERC721Received.selector;
                  } catch (bytes memory reason) {
                      if (reason.length == 0) {
                          revert("ERC721: transfer to non ERC721Receiver implementer");
                      } else {
                          assembly {
                              revert(add(32, reason), mload(reason))
                          }
                      }
                  }
              } else {
                  return true;
              }
          }
          /**
           * @dev Hook that is called before any token transfer. This includes minting
           * and burning.
           *
           * 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, ``from``'s `tokenId` will be burned.
           * - `from` and `to` are never both zero.
           *
           * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
           */
          function _beforeTokenTransfer(
              address from,
              address to,
              uint256 tokenId
          ) internal virtual {}
          /**
           * @dev Hook that is called after any transfer of tokens. This includes
           * minting and burning.
           *
           * Calling conditions:
           *
           * - when `from` and `to` are both non-zero.
           * - `from` and `to` are never both zero.
           *
           * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
           */
          function _afterTokenTransfer(
              address from,
              address to,
              uint256 tokenId
          ) internal virtual {}
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/ERC721Enumerable.sol)
      pragma solidity ^0.8.0;
      import "../ERC721.sol";
      import "./IERC721Enumerable.sol";
      /**
       * @dev This implements an optional extension of {ERC721} defined in the EIP that adds
       * enumerability of all the token ids in the contract as well as all token ids owned by each
       * account.
       */
      abstract contract ERC721Enumerable is ERC721, IERC721Enumerable {
          // Mapping from owner to list of owned token IDs
          mapping(address => mapping(uint256 => uint256)) private _ownedTokens;
          // Mapping from token ID to index of the owner tokens list
          mapping(uint256 => uint256) private _ownedTokensIndex;
          // Array with all token ids, used for enumeration
          uint256[] private _allTokens;
          // Mapping from token id to position in the allTokens array
          mapping(uint256 => uint256) private _allTokensIndex;
          /**
           * @dev See {IERC165-supportsInterface}.
           */
          function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC721) returns (bool) {
              return interfaceId == type(IERC721Enumerable).interfaceId || super.supportsInterface(interfaceId);
          }
          /**
           * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
           */
          function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
              require(index < ERC721.balanceOf(owner), "ERC721Enumerable: owner index out of bounds");
              return _ownedTokens[owner][index];
          }
          /**
           * @dev See {IERC721Enumerable-totalSupply}.
           */
          function totalSupply() public view virtual override returns (uint256) {
              return _allTokens.length;
          }
          /**
           * @dev See {IERC721Enumerable-tokenByIndex}.
           */
          function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
              require(index < ERC721Enumerable.totalSupply(), "ERC721Enumerable: global index out of bounds");
              return _allTokens[index];
          }
          /**
           * @dev Hook that is called before any token transfer. This includes minting
           * and burning.
           *
           * 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, ``from``'s `tokenId` will be burned.
           * - `from` cannot be the zero address.
           * - `to` cannot be the zero address.
           *
           * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
           */
          function _beforeTokenTransfer(
              address from,
              address to,
              uint256 tokenId
          ) internal virtual override {
              super._beforeTokenTransfer(from, to, tokenId);
              if (from == address(0)) {
                  _addTokenToAllTokensEnumeration(tokenId);
              } else if (from != to) {
                  _removeTokenFromOwnerEnumeration(from, tokenId);
              }
              if (to == address(0)) {
                  _removeTokenFromAllTokensEnumeration(tokenId);
              } else if (to != from) {
                  _addTokenToOwnerEnumeration(to, tokenId);
              }
          }
          /**
           * @dev Private function to add a token to this extension's ownership-tracking data structures.
           * @param to address representing the new owner of the given token ID
           * @param tokenId uint256 ID of the token to be added to the tokens list of the given address
           */
          function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
              uint256 length = ERC721.balanceOf(to);
              _ownedTokens[to][length] = tokenId;
              _ownedTokensIndex[tokenId] = length;
          }
          /**
           * @dev Private function to add a token to this extension's token tracking data structures.
           * @param tokenId uint256 ID of the token to be added to the tokens list
           */
          function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
              _allTokensIndex[tokenId] = _allTokens.length;
              _allTokens.push(tokenId);
          }
          /**
           * @dev Private function to remove a token from this extension's ownership-tracking data structures. Note that
           * while the token is not assigned a new owner, the `_ownedTokensIndex` mapping is _not_ updated: this allows for
           * gas optimizations e.g. when performing a transfer operation (avoiding double writes).
           * This has O(1) time complexity, but alters the order of the _ownedTokens array.
           * @param from address representing the previous owner of the given token ID
           * @param tokenId uint256 ID of the token to be removed from the tokens list of the given address
           */
          function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
              // To prevent a gap in from's tokens array, we store the last token in the index of the token to delete, and
              // then delete the last slot (swap and pop).
              uint256 lastTokenIndex = ERC721.balanceOf(from) - 1;
              uint256 tokenIndex = _ownedTokensIndex[tokenId];
              // When the token to delete is the last token, the swap operation is unnecessary
              if (tokenIndex != lastTokenIndex) {
                  uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
                  _ownedTokens[from][tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
                  _ownedTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
              }
              // This also deletes the contents at the last position of the array
              delete _ownedTokensIndex[tokenId];
              delete _ownedTokens[from][lastTokenIndex];
          }
          /**
           * @dev Private function to remove a token from this extension's token tracking data structures.
           * This has O(1) time complexity, but alters the order of the _allTokens array.
           * @param tokenId uint256 ID of the token to be removed from the tokens list
           */
          function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {
              // To prevent a gap in the tokens array, we store the last token in the index of the token to delete, and
              // then delete the last slot (swap and pop).
              uint256 lastTokenIndex = _allTokens.length - 1;
              uint256 tokenIndex = _allTokensIndex[tokenId];
              // When the token to delete is the last token, the swap operation is unnecessary. However, since this occurs so
              // rarely (when the last minted token is burnt) that we still do the swap here to avoid the gas cost of adding
              // an 'if' statement (like in _removeTokenFromOwnerEnumeration)
              uint256 lastTokenId = _allTokens[lastTokenIndex];
              _allTokens[tokenIndex] = lastTokenId; // Move the last token to the slot of the to-delete token
              _allTokensIndex[lastTokenId] = tokenIndex; // Update the moved token's index
              // This also deletes the contents at the last position of the array
              delete _allTokensIndex[tokenId];
              _allTokens.pop();
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
      pragma solidity ^0.8.0;
      /**
       * @dev Contract module that helps prevent reentrant calls to a function.
       *
       * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
       * available, which can be applied to functions to make sure there are no nested
       * (reentrant) calls to them.
       *
       * Note that because there is a single `nonReentrant` guard, functions marked as
       * `nonReentrant` may not call one another. This can be worked around by making
       * those functions `private`, and then adding `external` `nonReentrant` entry
       * points to them.
       *
       * TIP: If you would like to learn more about reentrancy and alternative ways
       * to protect against it, check out our blog post
       * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
       */
      abstract contract ReentrancyGuard {
          // Booleans are more expensive than uint256 or any type that takes up a full
          // word because each write operation emits an extra SLOAD to first read the
          // slot's contents, replace the bits taken up by the boolean, and then write
          // back. This is the compiler's defense against contract upgrades and
          // pointer aliasing, and it cannot be disabled.
          // The values being non-zero value makes deployment a bit more expensive,
          // but in exchange the refund on every call to nonReentrant will be lower in
          // amount. Since refunds are capped to a percentage of the total
          // transaction's gas, it is best to keep them low in cases like this one, to
          // increase the likelihood of the full refund coming into effect.
          uint256 private constant _NOT_ENTERED = 1;
          uint256 private constant _ENTERED = 2;
          uint256 private _status;
          constructor() {
              _status = _NOT_ENTERED;
          }
          /**
           * @dev Prevents a contract from calling itself, directly or indirectly.
           * Calling a `nonReentrant` function from another `nonReentrant`
           * function is not supported. It is possible to prevent this from happening
           * by making the `nonReentrant` function external, and making it call a
           * `private` function that does the actual work.
           */
          modifier nonReentrant() {
              // On the first call to nonReentrant, _notEntered will be true
              require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
              // Any calls to nonReentrant after this point will fail
              _status = _ENTERED;
              _;
              // By storing the original value once again, a refund is triggered (see
              // https://eips.ethereum.org/EIPS/eip-2200)
              _status = _NOT_ENTERED;
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
      pragma solidity ^0.8.0;
      import "../utils/Context.sol";
      /**
       * @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 Leaves the contract without owner. It will not be possible to call
           * `onlyOwner` functions anymore. Can only be called by the current owner.
           *
           * NOTE: Renouncing ownership will leave the contract without an owner,
           * thereby removing any functionality that is only available to the owner.
           */
          function renounceOwnership() public virtual onlyOwner {
              _transferOwnership(address(0));
          }
          /**
           * @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);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.5.0) (utils/cryptography/ECDSA.sol)
      pragma solidity ^0.8.0;
      import "../Strings.sol";
      /**
       * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
       *
       * These functions can be used to verify that a message was signed by the holder
       * of the private keys of a given address.
       */
      library ECDSA {
          enum RecoverError {
              NoError,
              InvalidSignature,
              InvalidSignatureLength,
              InvalidSignatureS,
              InvalidSignatureV
          }
          function _throwError(RecoverError error) private pure {
              if (error == RecoverError.NoError) {
                  return; // no error: do nothing
              } else if (error == RecoverError.InvalidSignature) {
                  revert("ECDSA: invalid signature");
              } else if (error == RecoverError.InvalidSignatureLength) {
                  revert("ECDSA: invalid signature length");
              } else if (error == RecoverError.InvalidSignatureS) {
                  revert("ECDSA: invalid signature 's' value");
              } else if (error == RecoverError.InvalidSignatureV) {
                  revert("ECDSA: invalid signature 'v' value");
              }
          }
          /**
           * @dev Returns the address that signed a hashed message (`hash`) with
           * `signature` or error string. This address can then be used for verification purposes.
           *
           * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
           * this function rejects them by requiring the `s` value to be in the lower
           * half order, and the `v` value to be either 27 or 28.
           *
           * IMPORTANT: `hash` _must_ be the result of a hash operation for the
           * verification to be secure: it is possible to craft signatures that
           * recover to arbitrary addresses for non-hashed data. A safe way to ensure
           * this is by receiving a hash of the original message (which may otherwise
           * be too long), and then calling {toEthSignedMessageHash} on it.
           *
           * Documentation for signature generation:
           * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
           * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
           *
           * _Available since v4.3._
           */
          function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
              // Check the signature length
              // - case 65: r,s,v signature (standard)
              // - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
              if (signature.length == 65) {
                  bytes32 r;
                  bytes32 s;
                  uint8 v;
                  // ecrecover takes the signature parameters, and the only way to get them
                  // currently is to use assembly.
                  assembly {
                      r := mload(add(signature, 0x20))
                      s := mload(add(signature, 0x40))
                      v := byte(0, mload(add(signature, 0x60)))
                  }
                  return tryRecover(hash, v, r, s);
              } else if (signature.length == 64) {
                  bytes32 r;
                  bytes32 vs;
                  // ecrecover takes the signature parameters, and the only way to get them
                  // currently is to use assembly.
                  assembly {
                      r := mload(add(signature, 0x20))
                      vs := mload(add(signature, 0x40))
                  }
                  return tryRecover(hash, r, vs);
              } else {
                  return (address(0), RecoverError.InvalidSignatureLength);
              }
          }
          /**
           * @dev Returns the address that signed a hashed message (`hash`) with
           * `signature`. This address can then be used for verification purposes.
           *
           * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
           * this function rejects them by requiring the `s` value to be in the lower
           * half order, and the `v` value to be either 27 or 28.
           *
           * IMPORTANT: `hash` _must_ be the result of a hash operation for the
           * verification to be secure: it is possible to craft signatures that
           * recover to arbitrary addresses for non-hashed data. A safe way to ensure
           * this is by receiving a hash of the original message (which may otherwise
           * be too long), and then calling {toEthSignedMessageHash} on it.
           */
          function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, signature);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
           *
           * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
           *
           * _Available since v4.3._
           */
          function tryRecover(
              bytes32 hash,
              bytes32 r,
              bytes32 vs
          ) internal pure returns (address, RecoverError) {
              bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
              uint8 v = uint8((uint256(vs) >> 255) + 27);
              return tryRecover(hash, v, r, s);
          }
          /**
           * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
           *
           * _Available since v4.2._
           */
          function recover(
              bytes32 hash,
              bytes32 r,
              bytes32 vs
          ) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, r, vs);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
           * `r` and `s` signature fields separately.
           *
           * _Available since v4.3._
           */
          function tryRecover(
              bytes32 hash,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) internal pure returns (address, RecoverError) {
              // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
              // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
              // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
              // signatures from current libraries generate a unique signature with an s-value in the lower half order.
              //
              // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
              // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
              // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
              // these malleable signatures as well.
              if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
                  return (address(0), RecoverError.InvalidSignatureS);
              }
              if (v != 27 && v != 28) {
                  return (address(0), RecoverError.InvalidSignatureV);
              }
              // If the signature is valid (and not malleable), return the signer address
              address signer = ecrecover(hash, v, r, s);
              if (signer == address(0)) {
                  return (address(0), RecoverError.InvalidSignature);
              }
              return (signer, RecoverError.NoError);
          }
          /**
           * @dev Overload of {ECDSA-recover} that receives the `v`,
           * `r` and `s` signature fields separately.
           */
          function recover(
              bytes32 hash,
              uint8 v,
              bytes32 r,
              bytes32 s
          ) internal pure returns (address) {
              (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
              _throwError(error);
              return recovered;
          }
          /**
           * @dev Returns an Ethereum Signed Message, created from a `hash`. This
           * produces hash corresponding to the one signed with the
           * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
           * JSON-RPC method as part of EIP-191.
           *
           * See {recover}.
           */
          function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
              // 32 is the length in bytes of hash,
              // enforced by the type signature above
              return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      32", hash));
          }
          /**
           * @dev Returns an Ethereum Signed Message, created from `s`. This
           * produces hash corresponding to the one signed with the
           * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
           * JSON-RPC method as part of EIP-191.
           *
           * See {recover}.
           */
          function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
              return keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
      ", Strings.toString(s.length), s));
          }
          /**
           * @dev Returns an Ethereum Signed Typed Data, created from a
           * `domainSeparator` and a `structHash`. This produces hash corresponding
           * to the one signed with the
           * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
           * JSON-RPC method as part of EIP-712.
           *
           * See {recover}.
           */
          function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
              return keccak256(abi.encodePacked("\\x19\\x01", domainSeparator, structHash));
          }
      }
      // SPDX-License-Identifier: MIT
      // 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.
       */
      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 Merklee 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)
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.5.0) (token/common/ERC2981.sol)
      pragma solidity ^0.8.0;
      import "../../interfaces/IERC2981.sol";
      import "../../utils/introspection/ERC165.sol";
      /**
       * @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.
       *
       * Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for
       * specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.
       *
       * Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the
       * fee is specified in basis points by default.
       *
       * IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See
       * https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the EIP. Marketplaces are expected to
       * voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.
       *
       * _Available since v4.5._
       */
      abstract contract ERC2981 is IERC2981, ERC165 {
          struct RoyaltyInfo {
              address receiver;
              uint96 royaltyFraction;
          }
          RoyaltyInfo private _defaultRoyaltyInfo;
          mapping(uint256 => RoyaltyInfo) private _tokenRoyaltyInfo;
          /**
           * @dev See {IERC165-supportsInterface}.
           */
          function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
              return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
          }
          /**
           * @inheritdoc IERC2981
           */
          function royaltyInfo(uint256 _tokenId, uint256 _salePrice)
              external
              view
              virtual
              override
              returns (address, uint256)
          {
              RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];
              if (royalty.receiver == address(0)) {
                  royalty = _defaultRoyaltyInfo;
              }
              uint256 royaltyAmount = (_salePrice * royalty.royaltyFraction) / _feeDenominator();
              return (royalty.receiver, royaltyAmount);
          }
          /**
           * @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a
           * fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an
           * override.
           */
          function _feeDenominator() internal pure virtual returns (uint96) {
              return 10000;
          }
          /**
           * @dev Sets the royalty information that all ids in this contract will default to.
           *
           * Requirements:
           *
           * - `receiver` cannot be the zero address.
           * - `feeNumerator` cannot be greater than the fee denominator.
           */
          function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
              require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
              require(receiver != address(0), "ERC2981: invalid receiver");
              _defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
          }
          /**
           * @dev Removes default royalty information.
           */
          function _deleteDefaultRoyalty() internal virtual {
              delete _defaultRoyaltyInfo;
          }
          /**
           * @dev Sets the royalty information for a specific token id, overriding the global default.
           *
           * Requirements:
           *
           * - `tokenId` must be already minted.
           * - `receiver` cannot be the zero address.
           * - `feeNumerator` cannot be greater than the fee denominator.
           */
          function _setTokenRoyalty(
              uint256 tokenId,
              address receiver,
              uint96 feeNumerator
          ) internal virtual {
              require(feeNumerator <= _feeDenominator(), "ERC2981: royalty fee will exceed salePrice");
              require(receiver != address(0), "ERC2981: Invalid parameters");
              _tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
          }
          /**
           * @dev Resets royalty information for the token id back to the global default.
           */
          function _resetTokenRoyalty(uint256 tokenId) internal virtual {
              delete _tokenRoyaltyInfo[tokenId];
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)
      pragma solidity ^0.8.0;
      import "../../utils/introspection/IERC165.sol";
      /**
       * @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;
      }
      // SPDX-License-Identifier: MIT
      // 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);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)
      pragma solidity ^0.8.0;
      import "../IERC721.sol";
      /**
       * @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);
      }
      // SPDX-License-Identifier: MIT
      // 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);
                  }
              }
          }
      }
      // SPDX-License-Identifier: MIT
      // 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;
          }
      }
      // SPDX-License-Identifier: MIT
      // 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);
          }
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
      pragma solidity ^0.8.0;
      import "./IERC165.sol";
      /**
       * @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;
          }
      }
      // SPDX-License-Identifier: MIT
      // 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);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.5.0) (token/ERC721/extensions/IERC721Enumerable.sol)
      pragma solidity ^0.8.0;
      import "../IERC721.sol";
      /**
       * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
       * @dev See https://eips.ethereum.org/EIPS/eip-721
       */
      interface IERC721Enumerable is IERC721 {
          /**
           * @dev Returns the total amount of tokens stored by the contract.
           */
          function totalSupply() external view returns (uint256);
          /**
           * @dev Returns a token ID owned by `owner` at a given `index` of its token list.
           * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
           */
          function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256);
          /**
           * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
           * Use along with {totalSupply} to enumerate all tokens.
           */
          function tokenByIndex(uint256 index) external view returns (uint256);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts (last updated v4.5.0) (interfaces/IERC2981.sol)
      pragma solidity ^0.8.0;
      import "./IERC165.sol";
      /**
       * @dev Interface for the NFT Royalty Standard.
       *
       * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
       * support for royalty payments across all NFT marketplaces and ecosystem participants.
       *
       * _Available since v4.5._
       */
      interface IERC2981 is IERC165 {
          /**
           * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
           * exchange. The royalty amount is denominated and should be payed in that same unit of exchange.
           */
          function royaltyInfo(uint256 tokenId, uint256 salePrice)
              external
              view
              returns (address receiver, uint256 royaltyAmount);
      }
      // SPDX-License-Identifier: MIT
      // OpenZeppelin Contracts v4.4.1 (interfaces/IERC165.sol)
      pragma solidity ^0.8.0;
      import "../utils/introspection/IERC165.sol";