pragma solidity =0.6.6;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint value) external returns (bool);
    function withdraw(uint) external;
}

contract UniswapV2Router02 is IUniswapV2Router02 {
    using SafeMath for uint;

    address public immutable override factory;
    address public immutable override WETH;

    modifier ensure(uint deadline) {
        require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
        _;
    }

    constructor(address _factory, address _WETH) public {
        factory = _factory;
        WETH = _WETH;
    }

    receive() external payable {
        assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
    }

    // **** ADD LIQUIDITY ****
    function _addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin
    ) internal virtual returns (uint amountA, uint amountB) {
        // create the pair if it doesn't exist yet
        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
            IUniswapV2Factory(factory).createPair(tokenA, tokenB);
        }
        (uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
            if (amountBOptimal <= amountBDesired) {
                require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
                assert(amountAOptimal <= amountADesired);
                require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
                (amountA, amountB) = (amountAOptimal, amountBDesired);
            }
        }
    }
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
        (amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
        liquidity = IUniswapV2Pair(pair).mint(to);
    }
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external virtual override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
        (amountToken, amountETH) = _addLiquidity(
            token,
            WETH,
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin
        );
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
        IWETH(WETH).deposit{value: amountETH}();
        assert(IWETH(WETH).transfer(pair, amountETH));
        liquidity = IUniswapV2Pair(pair).mint(to);
        // refund dust eth, if any
        if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH);
    }

    // **** REMOVE LIQUIDITY ****
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
        (uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
        (address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
        (amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
        require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
        require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
    }
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountToken, uint amountETH) {
        (amountToken, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, amountToken);
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
    }
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountToken, uint amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);
    }

    // **** REMOVE LIQUIDITY (supporting fee-on-transfer tokens) ****
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountETH) {
        (, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, IERC20(token).balanceOf(address(this)));
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        amountETH = removeLiquidityETHSupportingFeeOnTransferTokens(
            token, liquidity, amountTokenMin, amountETHMin, to, deadline
        );
    }

    // **** SWAP ****
    // requires the initial amount to have already been sent to the first pair
    function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual {
        for (uint i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0,) = UniswapV2Library.sortTokens(input, output);
            uint amountOut = amounts[i + 1];
            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(
                amount0Out, amount1Out, to, new bytes(0)
            );
        }
    }
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, to);
    }
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, to);
    }
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
    }
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
        // refund dust eth, if any
        if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]);
    }

    // **** SWAP (supporting fee-on-transfer tokens) ****
    // requires the initial amount to have already been sent to the first pair
    function _swapSupportingFeeOnTransferTokens(address[] memory path, address _to) internal virtual {
        for (uint i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0,) = UniswapV2Library.sortTokens(input, output);
            IUniswapV2Pair pair = IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output));
            uint amountInput;
            uint amountOutput;
            { // scope to avoid stack too deep errors
            (uint reserve0, uint reserve1,) = pair.getReserves();
            (uint reserveInput, uint reserveOutput) = input == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
            amountInput = IERC20(input).balanceOf(address(pair)).sub(reserveInput);
            amountOutput = UniswapV2Library.getAmountOut(amountInput, reserveInput, reserveOutput);
            }
            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOutput) : (amountOutput, uint(0));
            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
            pair.swap(amount0Out, amount1Out, to, new bytes(0));
        }
    }
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) {
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
        );
        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
        );
    }
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    )
        external
        virtual
        override
        payable
        ensure(deadline)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        uint amountIn = msg.value;
        IWETH(WETH).deposit{value: amountIn}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn));
        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
        );
    }
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    )
        external
        virtual
        override
        ensure(deadline)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
        );
        _swapSupportingFeeOnTransferTokens(path, address(this));
        uint amountOut = IERC20(WETH).balanceOf(address(this));
        require(amountOut >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        IWETH(WETH).withdraw(amountOut);
        TransferHelper.safeTransferETH(to, amountOut);
    }

    // **** LIBRARY FUNCTIONS ****
    function quote(uint amountA, uint reserveA, uint reserveB) public pure virtual override returns (uint amountB) {
        return UniswapV2Library.quote(amountA, reserveA, reserveB);
    }

    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut)
        public
        pure
        virtual
        override
        returns (uint amountOut)
    {
        return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
    }

    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut)
        public
        pure
        virtual
        override
        returns (uint amountIn)
    {
        return UniswapV2Library.getAmountIn(amountOut, reserveIn, reserveOut);
    }

    function getAmountsOut(uint amountIn, address[] memory path)
        public
        view
        virtual
        override
        returns (uint[] memory amounts)
    {
        return UniswapV2Library.getAmountsOut(factory, amountIn, path);
    }

    function getAmountsIn(uint amountOut, address[] memory path)
        public
        view
        virtual
        override
        returns (uint[] memory amounts)
    {
        return UniswapV2Library.getAmountsIn(factory, amountOut, path);
    }
}

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

library UniswapV2Library {
    using SafeMath for uint;

    // returns sorted token addresses, used to handle return values from pairs sorted in this order
    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
            ))));
    }

    // fetches and sorts the reserves for a pair
    function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) {
        (address token0,) = sortTokens(tokenA, tokenB);
        (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
        (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) {
        require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
        require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        amountB = amountA.mul(reserveB) / reserveA;
    }

    // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) {
        require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint amountInWithFee = amountIn.mul(997);
        uint numerator = amountInWithFee.mul(reserveOut);
        uint denominator = reserveIn.mul(1000).add(amountInWithFee);
        amountOut = numerator / denominator;
    }

    // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
        require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint numerator = reserveIn.mul(amountOut).mul(1000);
        uint denominator = reserveOut.sub(amountOut).mul(997);
        amountIn = (numerator / denominator).add(1);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[0] = amountIn;
        for (uint i; i < path.length - 1; i++) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]);
            amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
        }
    }

    // performs chained getAmountIn calculations on any number of pairs
    function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[amounts.length - 1] = amountOut;
        for (uint i = path.length - 1; i > 0; i--) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
            amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
        }
    }
}

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
    }

    function safeTransfer(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
    }

    function safeTransferFrom(address token, address from, address to, uint value) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
    }

    function safeTransferETH(address to, uint value) internal {
        (bool success,) = to.call{value:value}(new bytes(0));
        require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
    }
}

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/
// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
   /**
    * @dev Returns the addition of two unsigned integers, reverting on
    * overflow.
    *
    * Counterpart to Solidity's `+` operator.
    *
    * Requirements:
    *
    * - Addition cannot overflow.
    */
   function add(uint256 a, uint256 b) internal pure returns (uint256) {
       uint256 c = a + b;
       require(c >= a, "SafeMath: addition overflow");

       return c;
   }

   /**
    * @dev Returns the subtraction of two unsigned integers, reverting on
    * overflow (when the result is negative).
    *
    * Counterpart to Solidity's `-` operator.
    *
    * Requirements:
    *
    * - Subtraction cannot overflow.
    */
   function sub(uint256 a, uint256 b) internal pure returns (uint256) {
       return sub(a, b, "SafeMath: subtraction overflow");
   }

   /**
    * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
    * overflow (when the result is negative).
    *
    * Counterpart to Solidity's `-` operator.
    *
    * Requirements:
    *
    * - Subtraction cannot overflow.
    */
   function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
       require(b <= a, errorMessage);
       uint256 c = a - b;

       return c;
   }

   /**
    * @dev Returns the multiplication of two unsigned integers, reverting on
    * overflow.
    *
    * Counterpart to Solidity's `*` operator.
    *
    * Requirements:
    *
    * - Multiplication cannot overflow.
    */
   function mul(uint256 a, uint256 b) internal pure returns (uint256) {
       // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
       // benefit is lost if 'b' is also tested.
       // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
       if (a == 0) {
           return 0;
       }

       uint256 c = a * b;
       require(c / a == b, "SafeMath: multiplication overflow");

       return c;
   }

   /**
    * @dev Returns the integer division of two unsigned integers. Reverts on
    * division by zero. The result is rounded towards zero.
    *
    * Counterpart to Solidity's `/` operator. Note: this function uses a
    * `revert` opcode (which leaves remaining gas untouched) while Solidity
    * uses an invalid opcode to revert (consuming all remaining gas).
    *
    * Requirements:
    *
    * - The divisor cannot be zero.
    */
   function div(uint256 a, uint256 b) internal pure returns (uint256) {
       return div(a, b, "SafeMath: division by zero");
   }

   /**
    * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
    * division by zero. The result is rounded towards zero.
    *
    * Counterpart to Solidity's `/` operator. Note: this function uses a
    * `revert` opcode (which leaves remaining gas untouched) while Solidity
    * uses an invalid opcode to revert (consuming all remaining gas).
    *
    * Requirements:
    *
    * - The divisor cannot be zero.
    */
   function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
       require(b > 0, errorMessage);
       uint256 c = a / b;
       // assert(a == b * c + a % b); // There is no case in which this doesn't hold

       return c;
   }

   /**
    * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
    * Reverts when dividing by zero.
    *
    * Counterpart to Solidity's `%` operator. This function uses a `revert`
    * opcode (which leaves remaining gas untouched) while Solidity uses an
    * invalid opcode to revert (consuming all remaining gas).
    *
    * Requirements:
    *
    * - The divisor cannot be zero.
    */
   function mod(uint256 a, uint256 b) internal pure returns (uint256) {
       return mod(a, b, "SafeMath: modulo by zero");
   }

   /**
    * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
    * Reverts with custom message when dividing by zero.
    *
    * Counterpart to Solidity's `%` operator. This function uses a `revert`
    * opcode (which leaves remaining gas untouched) while Solidity uses an
    * invalid opcode to revert (consuming all remaining gas).
    *
    * Requirements:
    *
    * - The divisor cannot be zero.
    */
   function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
       require(b != 0, errorMessage);
       return a % b;
   }
}
// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/




/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
   /**
    * @dev Returns the amount of tokens in existence.
    */
   function totalSupply() external view returns (uint256);

   /**
    * @dev Returns the amount of tokens owned by `account`.
    */
   function balanceOf(address account) external view returns (uint256);

   /**
    * @dev Moves `amount` tokens from the caller's account to `recipient`.
    *
    * Returns a boolean value indicating whether the operation succeeded.
    *
    * Emits a {Transfer} event.
    */
   function transfer(address recipient, uint256 amount) external returns (bool);

   /**
    * @dev Returns the remaining number of tokens that `spender` will be
    * allowed to spend on behalf of `owner` through {transferFrom}. This is
    * zero by default.
    *
    * This value changes when {approve} or {transferFrom} are called.
    */
   function allowance(address owner, address spender) external view returns (uint256);

   /**
    * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
    *
    * Returns a boolean value indicating whether the operation succeeded.
    *
    * IMPORTANT: Beware that changing an allowance with this method brings the risk
    * that someone may use both the old and the new allowance by unfortunate
    * transaction ordering. One possible solution to mitigate this race
    * condition is to first reduce the spender's allowance to 0 and set the
    * desired value afterwards:
    * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    *
    * Emits an {Approval} event.
    */
   function approve(address spender, uint256 amount) external returns (bool);

   /**
    * @dev Moves `amount` tokens from `sender` to `recipient` using the
    * allowance mechanism. `amount` is then deducted from the caller's
    * allowance.
    *
    * Returns a boolean value indicating whether the operation succeeded.
    *
    * Emits a {Transfer} event.
    */
   function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

   /**
    * @dev Emitted when `value` tokens are moved from one account (`from`) to
    * another (`to`).
    *
    * Note that `value` may be zero.
    */
   event Transfer(address indexed from, address indexed to, uint256 value);

   /**
    * @dev Emitted when the allowance of a `spender` for an `owner` is set by
    * a call to {approve}. `value` is the new allowance.
    */
   event Approval(address indexed owner, address indexed spender, uint256 value);
}
// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/




/*
* @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 GSN 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 payable) {
       return msg.sender;
   }

   function _msgData() internal view virtual returns (bytes memory) {
       this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
       return msg.data;
   }
}
// Copyright (c) 2019-2020 revolutionpopuli.com

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.





// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/





/**
* @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 () internal {
       address msgSender = _msgSender();
       _owner = msgSender;
       emit OwnershipTransferred(address(0), msgSender);
   }

   /**
    * @dev Returns the address of the current owner.
    */
   function owner() public view 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 {
       emit OwnershipTransferred(_owner, address(0));
       _owner = 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");
       emit OwnershipTransferred(_owner, newOwner);
       _owner = newOwner;
   }
}

// Copyright (c) 2019-2020 revolutionpopuli.com

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.





// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/








/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
   using SafeMath for uint256;

   mapping (address => uint256) private _balances;

   mapping (address => mapping (address => uint256)) private _allowances;

   uint256 private _totalSupply;

   string private _name;
   string private _symbol;
   uint8 private _decimals;

   /**
    * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
    * a default value of 18.
    *
    * To select a different value for {decimals}, use {_setupDecimals}.
    *
    * All three of these values are immutable: they can only be set once during
    * construction.
    */
   constructor (string memory name_, string memory symbol_) public {
       _name = name_;
       _symbol = symbol_;
       _decimals = 18;
   }

   /**
    * @dev Returns the name of the token.
    */
   function name() public view returns (string memory) {
       return _name;
   }

   /**
    * @dev Returns the symbol of the token, usually a shorter version of the
    * name.
    */
   function symbol() public view returns (string memory) {
       return _symbol;
   }

   /**
    * @dev Returns the number of decimals used to get its user representation.
    * For example, if `decimals` equals `2`, a balance of `505` tokens should
    * be displayed to a user as `5,05` (`505 / 10 ** 2`).
    *
    * Tokens usually opt for a value of 18, imitating the relationship between
    * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
    * called.
    *
    * NOTE: This information is only used for _display_ purposes: it in
    * no way affects any of the arithmetic of the contract, including
    * {IERC20-balanceOf} and {IERC20-transfer}.
    */
   function decimals() public view returns (uint8) {
       return _decimals;
   }

   /**
    * @dev See {IERC20-totalSupply}.
    */
   function totalSupply() public view override returns (uint256) {
       return _totalSupply;
   }

   /**
    * @dev See {IERC20-balanceOf}.
    */
   function balanceOf(address account) public view override returns (uint256) {
       return _balances[account];
   }

   /**
    * @dev See {IERC20-transfer}.
    *
    * Requirements:
    *
    * - `recipient` cannot be the zero address.
    * - the caller must have a balance of at least `amount`.
    */
   function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
       _transfer(_msgSender(), recipient, amount);
       return true;
   }

   /**
    * @dev See {IERC20-allowance}.
    */
   function allowance(address owner, address spender) public view virtual override returns (uint256) {
       return _allowances[owner][spender];
   }

   /**
    * @dev See {IERC20-approve}.
    *
    * Requirements:
    *
    * - `spender` cannot be the zero address.
    */
   function approve(address spender, uint256 amount) public virtual override returns (bool) {
       _approve(_msgSender(), spender, amount);
       return true;
   }

   /**
    * @dev See {IERC20-transferFrom}.
    *
    * Emits an {Approval} event indicating the updated allowance. This is not
    * required by the EIP. See the note at the beginning of {ERC20}.
    *
    * Requirements:
    *
    * - `sender` and `recipient` cannot be the zero address.
    * - `sender` must have a balance of at least `amount`.
    * - the caller must have allowance for ``sender``'s tokens of at least
    * `amount`.
    */
   function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
       _transfer(sender, recipient, amount);
       _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
       return true;
   }

   /**
    * @dev Atomically increases the allowance granted to `spender` by the caller.
    *
    * This is an alternative to {approve} that can be used as a mitigation for
    * problems described in {IERC20-approve}.
    *
    * Emits an {Approval} event indicating the updated allowance.
    *
    * Requirements:
    *
    * - `spender` cannot be the zero address.
    */
   function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
       _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
       return true;
   }

   /**
    * @dev Atomically decreases the allowance granted to `spender` by the caller.
    *
    * This is an alternative to {approve} that can be used as a mitigation for
    * problems described in {IERC20-approve}.
    *
    * Emits an {Approval} event indicating the updated allowance.
    *
    * Requirements:
    *
    * - `spender` cannot be the zero address.
    * - `spender` must have allowance for the caller of at least
    * `subtractedValue`.
    */
   function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
       _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
       return true;
   }

   /**
    * @dev Moves tokens `amount` from `sender` to `recipient`.
    *
    * This is internal function is equivalent to {transfer}, and can be used to
    * e.g. implement automatic token fees, slashing mechanisms, etc.
    *
    * Emits a {Transfer} event.
    *
    * Requirements:
    *
    * - `sender` cannot be the zero address.
    * - `recipient` cannot be the zero address.
    * - `sender` must have a balance of at least `amount`.
    */
   function _transfer(address sender, address recipient, uint256 amount) internal virtual {
       require(sender != address(0), "ERC20: transfer from the zero address");
       require(recipient != address(0), "ERC20: transfer to the zero address");

       _beforeTokenTransfer(sender, recipient, amount);

       _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
       _balances[recipient] = _balances[recipient].add(amount);
       emit Transfer(sender, recipient, amount);
   }

   /** @dev Creates `amount` tokens and assigns them to `account`, increasing
    * the total supply.
    *
    * Emits a {Transfer} event with `from` set to the zero address.
    *
    * Requirements:
    *
    * - `to` cannot be the zero address.
    */
   function _mint(address account, uint256 amount) internal virtual {
       require(account != address(0), "ERC20: mint to the zero address");

       _beforeTokenTransfer(address(0), account, amount);

       _totalSupply = _totalSupply.add(amount);
       _balances[account] = _balances[account].add(amount);
       emit Transfer(address(0), account, amount);
   }

   /**
    * @dev Destroys `amount` tokens from `account`, reducing the
    * total supply.
    *
    * Emits a {Transfer} event with `to` set to the zero address.
    *
    * Requirements:
    *
    * - `account` cannot be the zero address.
    * - `account` must have at least `amount` tokens.
    */
   function _burn(address account, uint256 amount) internal virtual {
       require(account != address(0), "ERC20: burn from the zero address");

       _beforeTokenTransfer(account, address(0), amount);

       _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
       _totalSupply = _totalSupply.sub(amount);
       emit Transfer(account, address(0), amount);
   }

   /**
    * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
    *
    * This internal function is equivalent to `approve`, and can be used to
    * e.g. set automatic allowances for certain subsystems, etc.
    *
    * Emits an {Approval} event.
    *
    * Requirements:
    *
    * - `owner` cannot be the zero address.
    * - `spender` cannot be the zero address.
    */
   function _approve(address owner, address spender, uint256 amount) internal virtual {
       require(owner != address(0), "ERC20: approve from the zero address");
       require(spender != address(0), "ERC20: approve to the zero address");

       _allowances[owner][spender] = amount;
       emit Approval(owner, spender, amount);
   }

   /**
    * @dev Sets {decimals} to a value other than the default one of 18.
    *
    * WARNING: This function should only be called from the constructor. Most
    * applications that interact with token contracts will not expect
    * {decimals} to ever change, and may work incorrectly if it does.
    */
   function _setupDecimals(uint8 decimals_) internal {
       _decimals = decimals_;
   }

   /**
    * @dev Hook that is called before any transfer of tokens. This includes
    * minting and burning.
    *
    * Calling conditions:
    *
    * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
    * will be to transferred to `to`.
    * - when `from` is zero, `amount` tokens will be minted for `to`.
    * - when `to` is zero, `amount` of ``from``'s tokens 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 amount) internal virtual { }
}

// Copyright (c) 2019-2020 revolutionpopuli.com

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.





// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/






/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/
abstract contract Pausable is Context {
   /**
    * @dev Emitted when the pause is triggered by `account`.
    */
   event Paused(address account);

   /**
    * @dev Emitted when the pause is lifted by `account`.
    */
   event Unpaused(address account);

   bool private _paused;

   /**
    * @dev Initializes the contract in unpaused state.
    */
   constructor () internal {
       _paused = false;
   }

   /**
    * @dev Returns true if the contract is paused, and false otherwise.
    */
   function paused() public view returns (bool) {
       return _paused;
   }

   /**
    * @dev Modifier to make a function callable only when the contract is not paused.
    *
    * Requirements:
    *
    * - The contract must not be paused.
    */
   modifier whenNotPaused() virtual {
       require(!_paused, "Pausable: paused");
       _;
   }

   /**
    * @dev Modifier to make a function callable only when the contract is paused.
    *
    * Requirements:
    *
    * - The contract must be paused.
    */
   modifier whenPaused() {
       require(_paused, "Pausable: not paused");
       _;
   }

   /**
    * @dev Triggers stopped state.
    *
    * Requirements:
    *
    * - The contract must not be paused.
    */
   function _pause() internal virtual whenNotPaused {
       _paused = true;
       emit Paused(_msgSender());
   }

   /**
    * @dev Returns to normal state.
    *
    * Requirements:
    *
    * - The contract must be paused.
    */
   function _unpause() internal virtual whenPaused {
       _paused = false;
       emit Unpaused(_msgSender());
   }
}



contract PausableWithException is Pausable, Ownable {
   mapping(address => bool) public exceptions;

   modifier whenNotPaused() override {
       require(!paused() || hasException(_msgSender()), "Pausable: paused (and no exception)");

       _;
   }

   modifier whenNotPausedWithoutException() {
       require(!paused(), "Pausable: paused");

       _;
   }

   function hasException(address _account) public view returns (bool) {
       return exceptions[_account];
   }

   function setPausableException(address _account, bool _status) external whenNotPaused onlyOwner {
       exceptions[_account] = _status;
   }
}


contract Token is ERC20, PausableWithException {
   constructor(string memory name, string memory symbol) ERC20(name, symbol) {}

   function pause() public onlyOwner {
       super._pause();
   }

   function unpause() public onlyOwner {
       super._unpause();
   }

   function transfer(address recipient, uint256 amount) public override whenNotPaused returns (bool) {
       return super.transfer(recipient, amount);
   }

   function transferFrom(address sender, address recipient, uint256 amount) public override whenNotPausedWithoutException returns (bool) {
       return super.transferFrom(sender, recipient, amount);
   }

   function mint(address account, uint amount) public onlyOwner whenNotPaused {
       _mint(account, amount);
   }

   function burn(address account, uint amount) public onlyOwner {
       _burn(account, amount);
   }
}

// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/






// This contract was copied from https://github.com/OpenZeppelin/openzeppelin-contracts/




/**
* @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
    * ====
    */
   function isContract(address account) internal view returns (bool) {
       // This method relies on extcodesize, which returns 0 for contracts in
       // construction, since the code is only stored at the end of the
       // constructor execution.

       uint256 size;
       // solhint-disable-next-line no-inline-assembly
       assembly { size := extcodesize(account) }
       return size > 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");

       // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
       (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");

       // solhint-disable-next-line avoid-low-level-calls
       (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");

       // solhint-disable-next-line avoid-low-level-calls
       (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 v3.3._
    */
   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 v3.3._
    */
   function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
       require(isContract(target), "Address: delegate call to non-contract");

       // solhint-disable-next-line avoid-low-level-calls
       (bool success, bytes memory returndata) = target.delegatecall(data);
       return _verifyCallResult(success, returndata, errorMessage);
   }

   function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private 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

               // solhint-disable-next-line no-inline-assembly
               assembly {
                   let returndata_size := mload(returndata)
                   revert(add(32, returndata), returndata_size)
               }
           } else {
               revert(errorMessage);
           }
       }
   }
}


/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
   using SafeMath for uint256;
   using Address for address;

   function safeTransfer(IERC20 token, address to, uint256 value) internal {
       _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
   }

   function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
       _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
   }

   /**
    * @dev Deprecated. This function has issues similar to the ones found in
    * {IERC20-approve}, and its usage is discouraged.
    *
    * Whenever possible, use {safeIncreaseAllowance} and
    * {safeDecreaseAllowance} instead.
    */
   function safeApprove(IERC20 token, address spender, uint256 value) internal {
       // safeApprove should only be called when setting an initial allowance,
       // or when resetting it to zero. To increase and decrease it, use
       // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
       // solhint-disable-next-line max-line-length
       require((value == 0) || (token.allowance(address(this), spender) == 0),
           "SafeERC20: approve from non-zero to non-zero allowance"
       );
       _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
   }

   function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
       uint256 newAllowance = token.allowance(address(this), spender).add(value);
       _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
   }

   function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
       uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
       _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
   }

   /**
    * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
    * on the return value: the return value is optional (but if data is returned, it must not be false).
    * @param token The token targeted by the call.
    * @param data The call data (encoded using abi.encode or one of its variants).
    */
   function _callOptionalReturn(IERC20 token, bytes memory data) private {
       // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
       // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
       // the target address contains contract code and also asserts for success in the low-level call.

       bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
       if (returndata.length > 0) { // Return data is optional
           // solhint-disable-next-line max-line-length
           require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
       }
   }
}


// Copyright (c) 2019-2020 revolutionpopuli.com

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.






// Copyright (c) 2019-2020 revolutionpopuli.com

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.










contract TokenEscrow is Ownable {
   using SafeMath for uint256;
   using SafeERC20 for Token;

   struct Share {
       uint256 proportion;
       uint256 periods;
       uint256 periodLength;
   }

   uint256 public unlockStart;
   uint256 public totalShare;

   mapping(address => Share) public shares;
   mapping(address => uint256) public unlocked;

   Token public token;

   constructor(Token _token) {
       token = _token;
   }

   function setUnlockStart(uint256 _unlockStart) external virtual onlyOwner {
       require(unlockStart == 0, "unlockStart should be == 0");
       require(_unlockStart >= block.timestamp, "_unlockStart should be >= block.timestamp");

       unlockStart = _unlockStart;
   }

   function addShare(address _beneficiary, uint256 _proportion, uint256 _periods, uint256 _periodLength) external onlyOwner {
       shares[_beneficiary] = Share(shares[_beneficiary].proportion.add(_proportion),_periods,_periodLength);
       totalShare = totalShare.add(_proportion);
   }

   // If the time of freezing expired will return the funds to the owner.
   function unlockFor(address _beneficiary) public {
       require(unlockStart > 0, "unlockStart should be > 0");
       require(
           block.timestamp >= (unlockStart.add(shares[_beneficiary].periodLength)),
           "block.timestamp should be >= (unlockStart.add(shares[_beneficiary].periodLength))"
       );

       uint256 share = shares[_beneficiary].proportion;
       uint256 periodsSinceUnlockStart = ((block.timestamp).sub(unlockStart)).div(shares[_beneficiary].periodLength);

       if (periodsSinceUnlockStart < shares[_beneficiary].periods) {
           share = share.mul(periodsSinceUnlockStart).div(shares[_beneficiary].periods);
       }

       share = share.sub(unlocked[_beneficiary]);

       if (share > 0) {
           unlocked[_beneficiary] = unlocked[_beneficiary].add(share);
           uint256 unlockedToken = token.balanceOf(address(this)).mul(share).div(totalShare);
           totalShare = totalShare.sub(share);
           token.safeTransfer(_beneficiary,unlockedToken);
       }
   }
}


contract Creator {
   Token public token = new Token('RevolutionPopuli ERC20 Token', 'RVP');
   TokenEscrow public tokenEscrow;

   constructor() {
       token.transferOwnership(msg.sender);
   }

   function createTokenEscrow() external returns (TokenEscrow) {
       tokenEscrow = new TokenEscrow(token);
       tokenEscrow.transferOwnership(msg.sender);

       return tokenEscrow;
   }
}


contract TokenSale is Ownable {
   using SafeMath for uint256;
   using SafeERC20 for Token;

   uint constant public MIN_ETH = 0.1 ether; // !!! for real ICO change to 1 ether
   uint constant public WINDOW_DURATION = 23 hours; // !!! for real ICO change to 23 hours

   uint constant public MARKETING_SHARE = 200000000 ether;
   uint constant public TEAM_MEMBER_1_SHARE = 50000000 ether;
   uint constant public TEAM_MEMBER_2_SHARE = 50000000 ether;
   uint constant public TEAM_MEMBER_3_SHARE = 50000000 ether;
   uint constant public TEAM_MEMBER_4_SHARE = 50000000 ether;
   uint constant public REVPOP_FOUNDATION_SHARE = 200000000 ether;
   uint constant public REVPOP_FOUNDATION_PERIOD_LENGTH = 365 days; // !!! for real ICO change to 365 days
   uint constant public REVPOP_FOUNDATION_PERIODS = 10; // 10 years (!!! for real ICO it would be 10 years)
   uint constant public REVPOP_COMPANY_SHARE = 200000000 ether;
   uint constant public REVPOP_COMPANY_PERIOD_LENGTH = 365 days; // !!! for real ICO change to 365 days
   uint constant public REVPOP_COMPANY_PERIODS = 10; // 10 years (!!! for real ICO it would be 10 years)

   address[9] public wallets = [
       // RevPop.org foundation
       0x26be1e82026BB50742bBF765c8b1665bCB763c4c,

       // RevPop company
       0x4A2d3b4475dA7E634154F1868e689705bDCEEF4c,

       // Marketing
       0x73d3F88BF15EB48e94E6583968041cC850d61D62,

       // Team member 1
       0x1F3eFCe792f9744d919eee34d23e054631351eBc,

       // Team member 2
       0xEB7bb38D821219aE20d3Df7A80A161563CDe5f1b,

       // Team member 3
       0x9F3868cF5FEdb90Df9D9974A131dE6B56B3aA7Ca,

       // Team member 4
       0xE7320724CA4C20aEb193472D3082593f6c58A3C5,

       // Unsold tokens taker
       0xCde8311aa7AAbECDEf84179D93a04005C8C549c0,

       // Beneficiarry
       0x8B104136F8c1FC63fBA34cb46c42c7af5532f80e
   ];

   Token public token;                   // The Token token itself
   TokenEscrow public tokenEscrow;

   uint public totalSupply;           // Total Token amount created

   uint public firstWindowStartTime;  // Time of window 1 opening
   uint public createPerFirstWindow;  // Tokens sold in window 1

   uint public otherWindowsStartTime; // Time of other windows opening
   uint public numberOfOtherWindows;  // Number of other windows
   uint public createPerOtherWindow;  // Tokens sold in each window after window 1

   uint public totalBoughtTokens;
   uint public totalRaisedETH;
   uint public totalBulkPurchasedTokens;

   uint public collectedUnsoldTokensBeforeWindow = 0;

   bool public initialized = false;
   bool public tokensPerPeriodAreSet = false;
   bool public distributedShares = false;
   bool public began = false;
   bool public tokenSalePaused = false;

   mapping(uint => uint) public dailyTotals;
   mapping(uint => mapping(address => uint)) public userBuys;
   mapping(uint => mapping(address => bool)) public claimed;

   event LogBuy           (uint window, address user, uint amount);
   event LogClaim         (uint window, address user, uint amount);
   event LogCollect       (uint amount);
   event LogCollectUnsold (uint amount);

   constructor(Creator creator) {
       token = creator.token();

       require(token.totalSupply() == 0, "Total supply of Token should be 0");

       tokenEscrow = creator.createTokenEscrow();

       require(tokenEscrow.owner() == address(this), "Invalid owner of the TokenEscrow");
       require(tokenEscrow.unlockStart() == 0, "TokenEscrow.unlockStart should be 0");
   }

   function renounceOwnership() public override onlyOwner {
       require(address(this).balance == 0, "address(this).balance should be == 0");

       super.renounceOwnership();
   }

   function initialize(
       uint _totalSupply,
       uint _firstWindowStartTime,
       uint _otherWindowsStartTime,
       uint _numberOfOtherWindows
   ) public onlyOwner {
       require(token.owner() == address(this), "Invalid owner of the Token");
       token.setPausableException(address(tokenEscrow), true);
       token.setPausableException(address(this), true);
       token.setPausableException(wallets[2], true);
       token.setPausableException(wallets[7], true);

       require(initialized == false, "initialized should be == false");
       require(_totalSupply > 0, "_totalSupply should be > 0");
       require(_firstWindowStartTime < _otherWindowsStartTime, "_firstWindowStartTime should be < _otherWindowsStartTime");
       require(_numberOfOtherWindows > 0, "_numberOfOtherWindows should be > 0");
       require(_totalSupply > totalReservedTokens(), "_totalSupply should be more than totalReservedTokens()");

       numberOfOtherWindows = _numberOfOtherWindows;
       totalSupply = _totalSupply;
       firstWindowStartTime = _firstWindowStartTime;
       otherWindowsStartTime = _otherWindowsStartTime;

       initialized = true;

       token.mint(address(this), totalSupply);
   }

   function addBulkPurchasers(address[] memory _purchasers, uint[] memory _tokens) public onlyOwner {
       require(initialized == true, "initialized should be == true");
       require(tokensPerPeriodAreSet == false, "tokensPerPeriodAreSet should be == false");

       uint count = _purchasers.length;

       require(count > 0, "count should be > 0");
       require(count == _tokens.length, "count should be == _tokens.length");

       for (uint i = 0; i < count; i++) {
           require(_tokens[i] > 0, "_tokens[i] should be > 0");
           token.safeTransfer(_purchasers[i], _tokens[i]);
           totalBulkPurchasedTokens = totalBulkPurchasedTokens.add(_tokens[i]);
       }

       require(
           token.balanceOf(address(this)) > totalReservedTokens(),
           "token.balanceOf(address(this)) should be > totalReservedTokens() after bulk purchases"
       );
   }

   function setTokensPerPeriods(uint _firstPeriodTokens, uint _otherPeriodTokens) public onlyOwner {
       require(initialized == true, "initialized should be == true");
       require(began == false, "began should be == false");

       tokensPerPeriodAreSet = true;

       uint totalTokens = _firstPeriodTokens.add(_otherPeriodTokens.mul(numberOfOtherWindows));

       require(
           totalSupply.sub(totalReservedTokens()).sub(totalBulkPurchasedTokens) == totalTokens,
           "totalSupply.sub(totalReservedTokens()).sub(totalBulkPurchasedTokens) should be == totalTokens"
       );

       createPerFirstWindow = _firstPeriodTokens;
       createPerOtherWindow = _otherPeriodTokens;
   }

   function distributeShares() public onlyOwner {
       require(tokensPerPeriodAreSet == true, "tokensPerPeriodAreSet should be == true");
       require(distributedShares == false, "distributedShares should be == false");

       distributedShares = true;

       token.safeTransfer(address(tokenEscrow), REVPOP_COMPANY_SHARE.add(REVPOP_FOUNDATION_SHARE));
       token.safeTransfer(wallets[2], MARKETING_SHARE);
       token.safeTransfer(wallets[3], TEAM_MEMBER_1_SHARE);
       token.safeTransfer(wallets[4], TEAM_MEMBER_2_SHARE);
       token.safeTransfer(wallets[5], TEAM_MEMBER_3_SHARE);
       token.safeTransfer(wallets[6], TEAM_MEMBER_4_SHARE);

       tokenEscrow.addShare(wallets[0], 50, REVPOP_FOUNDATION_PERIODS, REVPOP_FOUNDATION_PERIOD_LENGTH);
       tokenEscrow.addShare(wallets[1], 50, REVPOP_COMPANY_PERIODS, REVPOP_COMPANY_PERIOD_LENGTH);
       tokenEscrow.setUnlockStart(time());

       // We pause all transfers and minting.
       // We allow to use transfer() function ONLY for tokenEscrow contract,
       // because it is an escrow and it should allow to transfer tokens to a certain party.
       pauseTokenTransfer();
   }

   function totalReservedTokens() internal pure returns (uint) {
       return MARKETING_SHARE
           .add(TEAM_MEMBER_1_SHARE)
           .add(TEAM_MEMBER_2_SHARE)
           .add(TEAM_MEMBER_3_SHARE)
           .add(TEAM_MEMBER_4_SHARE)
           .add(REVPOP_COMPANY_SHARE)
           .add(REVPOP_FOUNDATION_SHARE);
   }

   function begin() public onlyOwner {
       require(distributedShares == true, "distributedShares should be == true");
       require(began == false, "began should be == false");

       began = true;
   }

   function pauseTokenTransfer() public onlyOwner {
       token.pause();
   }

   function unpauseTokenTransfer() public onlyOwner {
       token.unpause();
   }

   function pauseTokenSale() public onlyOwner {
       tokenSalePaused = true;
   }

   function unpauseTokenSale() public onlyOwner {
       tokenSalePaused = false;
   }

   function burnTokens(address account, uint amount) public onlyOwner {
       token.burn(account, amount);
   }

   function removePausableException(address _address) public onlyOwner {
       token.setPausableException(_address, false);
   }

   function time() internal view returns (uint) {
       return block.timestamp;
   }

   function today() public view returns (uint) {
       return windowFor(time());
   }

   function windowDuration() public virtual pure returns (uint) {
       return WINDOW_DURATION;
   }

   // Each window is windowDuration() (23 hours) long so that end-of-window rotates
   // around the clock for all timezones.
   function windowFor(uint timestamp) public view returns (uint) {
       return timestamp < otherWindowsStartTime
       ? 0
       : timestamp.sub(otherWindowsStartTime).div(windowDuration()).add(1);
   }

   function createOnWindow(uint window) public view returns (uint) {
       return window == 0 ? createPerFirstWindow : createPerOtherWindow;
   }

   // This method provides the buyer some protections regarding which
   // day the buy order is submitted and the maximum price prior to
   // applying this payment that will be allowed.
   function buyWithLimit(uint window, uint limit) public payable {
       require(began == true, "began should be == true");
       require(tokenSalePaused == false, "tokenSalePaused should be == false");
       require(time() >= firstWindowStartTime, "time() should be >= firstWindowStartTime");
       require(today() <= numberOfOtherWindows, "today() should be <= numberOfOtherWindows");
       require(msg.value >= MIN_ETH, "msg.value should be >= MIN_ETH");
       require(window >= today(), "window should be >= today()");
       require(window <= numberOfOtherWindows, "window should be <= numberOfOtherWindows");

       if (limit != 0) {
           require(dailyTotals[window] <= limit, "dailyTotals[window] should be <= limit");
       }

       userBuys[window][msg.sender] = userBuys[window][msg.sender].add(msg.value);
       dailyTotals[window] = dailyTotals[window].add(msg.value);
       totalRaisedETH = totalRaisedETH.add(msg.value);

       emit LogBuy(window, msg.sender, msg.value);
   }

   function buy() public payable {
       buyWithLimit(today(), 0);
   }

   fallback() external payable {
       buy();
   }

   receive() external payable {
       buy();
   }

   function claim(uint window) public {
       require(began == true, "began should be == true");
       require(today() > window, "today() should be > window");

       if (claimed[window][msg.sender] || dailyTotals[window] == 0 || userBuys[window][msg.sender] == 0) {
           return;
       }

       // 100 ether below is 100% * 10^18
       uint256 userEthShare = userBuys[window][msg.sender].mul(100 ether).div(dailyTotals[window]);
       uint256 reward = (createOnWindow(window)).mul(userEthShare).div(100 ether);

       totalBoughtTokens = totalBoughtTokens.add(reward);
       claimed[window][msg.sender] = true;
       token.safeTransfer(msg.sender, reward);

       emit LogClaim(window, msg.sender, reward);
   }

   function claimAll() public {
       require(began == true, "began should be == true");

       for (uint i = 0; i < today(); i++) {
           claim(i);
       }
   }

   // Crowdsale owners can collect ETH  number of times
   function collect() public {
       require(began == true, "began should be == true");
       require(today() > 0, "today() should be > 0");
       // Prevent recycling during window 0

       uint balance = address(this).balance;
       payable(wallets[8]).transfer(address(this).balance);

       emit LogCollect(balance);
   }

   function collectUnsoldTokens(uint window) public {
       require(began == true, "began should be == true");
       require(today() > 0, "today() should be > 0");
       require(window <= today(), "window should be <= today()");
       require(window > collectedUnsoldTokensBeforeWindow, "window should be > collectedUnsoldTokensBeforeWindow");

       uint unsoldTokens = 0;

       for (uint i = collectedUnsoldTokensBeforeWindow; i < window; i++) {
           uint dailyTotal = dailyTotals[i];

           if (dailyTotal == 0) {
               unsoldTokens = unsoldTokens.add(i == 0 ? createPerFirstWindow : createPerOtherWindow);
           }
       }

       collectedUnsoldTokensBeforeWindow = window;

       if (unsoldTokens > 0) {
           token.safeTransfer(wallets[7], unsoldTokens);
       }

       emit LogCollectUnsold(unsoldTokens);
   }
}