/*
"The Proof of Existence protocol"


From truth=authority to truth=money, how much has changed? In the Proof of Existence protocol, truth=human existence
Increasing attention to decentralized ledger solutions over the recent decade gave rise to a whole class of projects 
oriented toward encryption methods and consensus mechanisms. These scientific pursuits have never been exposed to 
capital in such a direct manner. 

An abundance of capital has created a massive research wave on a variety of decentralized transaction verification systems. 
Simultaneously, biometric processing has evolved to a stage where search and matching operations can maintain privacy while 
liveness detection error probabilities decline by the day.
Proof of Existence is a network based on cryptographically secure bio-authorized nodes. Using solutions that provide private 
search and matching operations and liveness detection algorithms, users will be able to 
deploy nodes to create a public permissionless financial network based on consensus between human nodes who share the fees and ownership of the network in an equal manner.
Modern decentralized verification systems rely on the concept of material obligations to prevent malicious activity—Proof-of-work (PoW) blockchain systems blacklist mining equipment, 
Proof-of-Stake (PoS) slashes tokens. The main focus of these protection mechanisms is to create a system in which attacks are unimaginably costly for any hypothetical predator. 
This reliance rises from problems of distrust on many levels, but most importantly because any trust system requires an instrument for preventing malicious activity. 
As human nodes are not created through mining farms or monetary obligations in the form of staking, they are not exposed to the same angle of attack. 
The Proof of Existence network will prevent malicious activity by blacklisting biometric data, meaning that your biometric identity becomes the stake.
Human nodes are created through cryptobiometric authentication, which is a combination of cryptographically secure matching and liveness detection mechanisms to verify the uniqueness and existence of real human beings. 

Thus, the user's pseudonymous biometric identity becomes the stake that gives access to the creation of a node that verifies transactions. 
This approach mitigates the problem of the disproportion of power in decentralized systems such as mining cartels or validator oligopolies. 
In the Proof of Existence network, only one node derives from one biometric identity. 
This also means that every node is equal in terms of voting and computation power, while rewards for verification and storage are equally distributed among the human nodes.
As the right to launch human nodes is not entangled with a native token, it allows the implementation of any monetary system without the necessity of conforming to 
the requirements of capital-based Sybil-defense systems. With human nodes replacing staked assets, it is now possible to avoid a disproportion of token emission between those who stake, validate, or simply hold the asset.

Proof of Existence will implement the Fath hypothesis as the mechanism for monetary supply adjustment and proportional distribution of emission. 
The main idea behind the Fath hypothesis is a full-reserve system that calculates the amount of goods and services sold in equal periods of time. 
If the value created in the new period is greater than the value in the previous one by 1%, the Fath protocol issues 1% of the supply and delivers 
it to every single wallet in the network, depending on the account balance (savings). If the wallet holds 1% of the supply during the emission, it gets 1% of the minted tokens directly from the protocol.
Any person in the world, no matter where they are from or who they are, can become a human node, as long as that person has access to devices 
that can conduct biometric processing (for example, a smartphone with a camera and biometric processing applications for recognition) or other verified hardware. 
The system delivers the equality of every single human node by deriving only one node from one biometric identity and mitigates any disproportion of power due to reward equality of individuals. 
As the system implements the Fath hypothesis, which negates the effect of devaluation on agents of the system, this narrows gaps between the users of the network 
as the emitted value is distributed proportionally to every participant.
The main goal of Proof of Existence is to create a stable and just financial network that relies on the existence of human life itself. 

We aim to alleviate all the intermediaries that stand between a person and his ability to become a validator of transactions. 
Proof of Existence strives to deliver easy node creation flows and make it natural for any human to verify their unique existence privately in any digital service. 
We acknowledge the power of a strong and idea-driven community, and that is why Proof of Existence will be an open-source project. 
We believe that by joining forces together with passionate minds and hearts throughout the world we will be able to achieve a balanced state of the system that 
will ensure our economic freedom and stability and safeguard the future of our children, grandchildren, and many generations to come. 
The symbiosis of humans and technology is inevitable, and Proof of Existence is just a small but important step in the large transcendence period that we are all going through.



Website, Telegram and Socials will be visible on Dextools in 2 hours.


*/

// SPDX-License-Identifier: MIT


pragma solidity ^0.8.9;

/**
 * @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);
}

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

/**
 * @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, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override 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 this function is
     * overridden;
     *
     * 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 virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual 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);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        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] + 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) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * This 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);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(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:
     *
     * - `account` 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 += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(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);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(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 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 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 {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been 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 _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

/**
 * @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() {
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(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");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) internal {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

/**
 * @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() {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual 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() {
        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());
    }
}

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 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 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;
}

contract ProofofExistence is ERC20, Ownable, Pausable {

    // variables
    
    uint256 private initialSupply;
   
    uint256 private denominator = 100;

    uint256 private swapThreshold = 0.0000005 ether; // The contract will only swap to ETH, once the fee tokens reach the specified threshold
    
    uint256 private devTaxBuy;
    uint256 private liquidityTaxBuy;
   
    
    uint256 private devTaxSell;
    uint256 private liquidityTaxSell;
    uint256 public maxWallet;
    
    address private devTaxWallet;
    address private liquidityTaxWallet;
    
    
    // Mappings
    
    mapping (address => bool) private blacklist;
    mapping (address => bool) private excludeList;
   
    
    mapping (string => uint256) private buyTaxes;
    mapping (string => uint256) private sellTaxes;
    mapping (string => address) private taxWallets;
    
    bool public taxStatus = true;
    
    IUniswapV2Router02 private uniswapV2Router02;
    IUniswapV2Factory private uniswapV2Factory;
    IUniswapV2Pair private uniswapV2Pair;
    
    constructor(string memory _tokenName,string memory _tokenSymbol,uint256 _supply) ERC20(_tokenName, _tokenSymbol) payable
    {
        initialSupply =_supply * (10**18);
        maxWallet = initialSupply * 3 / 100; //2% of the supply
        _setOwner(msg.sender);
        uniswapV2Router02 = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Factory = IUniswapV2Factory(uniswapV2Router02.factory());
        uniswapV2Pair = IUniswapV2Pair(uniswapV2Factory.createPair(address(this), uniswapV2Router02.WETH()));
        taxWallets["liquidity"] = address(0);
        setBuyTax(5,1); //dev tax, liquidity tax
        setSellTax(7,1); //dev tax, liquidity tax
        setTaxWallets(0x259EdB794ab48Aa6963D15D82Ef68064679cB297); // replace this with your wallet
        exclude(msg.sender);
        exclude(address(this));
        exclude(devTaxWallet);
        _mint(msg.sender, initialSupply);
    }
    
    
    uint256 private devTokens;
    uint256 private liquidityTokens;
    
    
    /**
     * @dev Calculates the tax, transfer it to the contract. If the user is selling, and the swap threshold is met, it executes the tax.
     */
    function handleTax(address from, address to, uint256 amount) private returns (uint256) {
        address[] memory sellPath = new address[](2);
        sellPath[0] = address(this);
        sellPath[1] = uniswapV2Router02.WETH();
        
        if(!isExcluded(from) && !isExcluded(to)) {
            uint256 tax;
            uint256 baseUnit = amount / denominator;
            if(from == address(uniswapV2Pair)) {
                tax += baseUnit * buyTaxes["dev"];
                tax += baseUnit * buyTaxes["liquidity"];
               
                
                if(tax > 0) {
                    _transfer(from, address(this), tax);   
                }
                
                
                devTokens += baseUnit * buyTaxes["dev"];
                liquidityTokens += baseUnit * buyTaxes["liquidity"];

            } else if(to == address(uniswapV2Pair)) {
                
                tax += baseUnit * sellTaxes["dev"];
                tax += baseUnit * sellTaxes["liquidity"];
                
                
                if(tax > 0) {
                    _transfer(from, address(this), tax);   
                }
                
               
                devTokens += baseUnit * sellTaxes["dev"];
                liquidityTokens += baseUnit * sellTaxes["liquidity"];
                
                
                uint256 taxSum =  devTokens + liquidityTokens;
                
                if(taxSum == 0) return amount;
                
                uint256 ethValue = uniswapV2Router02.getAmountsOut( devTokens + liquidityTokens, sellPath)[1];
                
                if(ethValue >= swapThreshold) {
                    uint256 startBalance = address(this).balance;

                    uint256 toSell = devTokens + liquidityTokens / 2 ;
                    
                    _approve(address(this), address(uniswapV2Router02), toSell);
            
                    uniswapV2Router02.swapExactTokensForETH(
                        toSell,
                        0,
                        sellPath,
                        address(this),
                        block.timestamp
                    );
                    
                    uint256 ethGained = address(this).balance - startBalance;
                    
                    uint256 liquidityToken = liquidityTokens / 2;
                    uint256 liquidityETH = (ethGained * ((liquidityTokens / 2 * 10**18) / taxSum)) / 10**18;
                    
                    
                    uint256 devETH = (ethGained * ((devTokens * 10**18) / taxSum)) / 10**18;
                   
                    
                    _approve(address(this), address(uniswapV2Router02), liquidityToken);
                    
                    uniswapV2Router02.addLiquidityETH{value: liquidityETH}(
                        address(this),
                        liquidityToken,
                        0,
                        0,
                        taxWallets["liquidity"],
                        block.timestamp
                    );
                    
                    uint256 remainingTokens = (devTokens + liquidityTokens) - (toSell + liquidityToken);
                    
                    if(remainingTokens > 0) {
                        _transfer(address(this), taxWallets["dev"], remainingTokens);
                    }
                    
                    
                   (bool success,) = taxWallets["dev"].call{value: devETH}("");
                   require(success, "transfer to  dev wallet failed");
                    
                    
                    if(ethGained - ( devETH + liquidityETH) > 0) {
                       (bool success1,) = taxWallets["dev"].call{value: ethGained - (devETH + liquidityETH)}("");
                        require(success1, "transfer to  dev wallet failed");
                    }

                    
                    
                    
                    devTokens = 0;
                    liquidityTokens = 0;
                    
                }
                
            }
            
            amount -= tax;
            if (to != address(uniswapV2Pair)){
                require(balanceOf(to) + amount <= maxWallet, "maxWallet limit exceeded");
            }
           
        }
        
        return amount;
    }
    
    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal override virtual {
        require(!paused(), "ERC20: token transfer while paused");
        require(!isBlacklisted(msg.sender), "ERC20: sender blacklisted");
        require(!isBlacklisted(recipient), "ERC20: recipient blacklisted");
        require(!isBlacklisted(tx.origin), "ERC20: sender blacklisted");
        
        if(taxStatus) {
            amount = handleTax(sender, recipient, amount);   
        }

        super._transfer(sender, recipient, amount);
    }
    
    /**
     * @dev Triggers the tax handling functionality
     */
    function triggerTax() public onlyOwner {
        handleTax(address(0), address(uniswapV2Pair), 0);
    }
    
    /**
     * @dev Pauses transfers on the token.
     */
    function pause() public onlyOwner {
        require(!paused(), "ERC20: Contract is already paused");
        _pause();
    }

    /**
     * @dev Unpauses transfers on the token.
     */
    function unpause() public onlyOwner {
        require(paused(), "ERC20: Contract is not paused");
        _unpause();
    }

     /**
     * @dev set max wallet limit per address.
     */

    function setMaxWallet (uint256 amount) external onlyOwner {
        require (amount > 10000, "NO rug pull");
        maxWallet = amount * 10**18;
    }
    
    /**
     * @dev Burns tokens from caller address.
     */
    function burn(uint256 amount) public onlyOwner {
        _burn(msg.sender, amount);
    }
    
    /**
     * @dev Blacklists the specified account (Disables transfers to and from the account).
     */
    function enableBlacklist(address account) public onlyOwner {
        require(!blacklist[account], "ERC20: Account is already blacklisted");
        blacklist[account] = true;
    }
    
    /**
     * @dev Remove the specified account from the blacklist.
     */
    function disableBlacklist(address account) public onlyOwner {
        require(blacklist[account], "ERC20: Account is not blacklisted");
        blacklist[account] = false;
    }
    
    /**
     * @dev Excludes the specified account from tax.
     */
    function exclude(address account) public onlyOwner {
        require(!isExcluded(account), "ERC20: Account is already excluded");
        excludeList[account] = true;
    }
    
    /**
     * @dev Re-enables tax on the specified account.
     */
    function removeExclude(address account) public onlyOwner {
        require(isExcluded(account), "ERC20: Account is not excluded");
        excludeList[account] = false;
    }
    
    /**
     * @dev Sets tax for buys.
     */
    function setBuyTax(uint256 dev,uint256 liquidity) public onlyOwner {
        buyTaxes["dev"] = dev;
        buyTaxes["liquidity"] = liquidity;
       
    }
    
    /**
     * @dev Sets tax for sells.
     */
    function setSellTax(uint256 dev, uint256 liquidity) public onlyOwner {

        sellTaxes["dev"] = dev;
        sellTaxes["liquidity"] = liquidity;
        
    }
    
    /**
     * @dev Sets wallets for taxes.
     */
    function setTaxWallets(address dev) public onlyOwner {
        taxWallets["dev"] = dev;
        
    }

    function claimStuckTokens(address _token) external onlyOwner {
 
        if (_token == address(0x0)) {
            payable(owner()).transfer(address(this).balance);
            return;
        }
        IERC20 erc20token = IERC20(_token);
        uint256 balance = erc20token.balanceOf(address(this));
        erc20token.transfer(owner(), balance);
    }
    
    /**
     * @dev Enables tax globally.
     */
    function enableTax() public onlyOwner {
        require(!taxStatus, "ERC20: Tax is already enabled");
        taxStatus = true;
    }
    
    /**
     * @dev Disables tax globally.
     */
    function disableTax() public onlyOwner {
        require(taxStatus, "ERC20: Tax is already disabled");
        taxStatus = false;
    }
    
    /**
     * @dev Returns true if the account is blacklisted, and false otherwise.
     */
    function isBlacklisted(address account) public view returns (bool) {
        return blacklist[account];
    }
    
    /**
     * @dev Returns true if the account is excluded, and false otherwise.
     */
    function isExcluded(address account) public view returns (bool) {
        return excludeList[account];
    }
    
    receive() external payable {}
}