/*
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                                                             Copyright by 1inch Corporation
                                                                 https://1inch.exchange

---
Deployer wallet address:
0x7E1E3334130355799F833ffec2D731BCa3E68aF6

Signed raw transaction for chainId 1:
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---
*/
// File: @openzeppelin/contracts/math/Math.sol

pragma solidity ^0.6.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.6.0;

/**
 * @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) {
        // Solidity only automatically asserts when dividing by 0
        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;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.6.0;

/**
 * @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);
}

// File: contracts/ChiToken.sol

pragma solidity ^0.6.0;





abstract contract ERC20WithoutTotalSupply is IERC20 {
    using SafeMath for uint256;

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

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function allowance(address owner, address spender) public view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    function _transfer(address sender, address recipient, uint256 amount) internal {
        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    function _approve(address owner, address spender, uint256 amount) internal {
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _mint(address account, uint256 amount) internal {
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal {
        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        emit Transfer(account, address(0), amount);
    }

    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount, "ERC20: burn amount exceeds allowance"));
    }
}


contract ChiToken is IERC20, ERC20WithoutTotalSupply {
    string constant public name = "Chi Gastoken by 1inch";
    string constant public symbol = "CHI";
    uint8 constant public decimals = 0;

    uint256 public totalMinted;
    uint256 public totalBurned;

    function totalSupply() public view override returns(uint256) {
        return totalMinted.sub(totalBurned);
    }

    function mint(uint256 value) public {
        uint256 offset = totalMinted;
        assembly {
            mstore(0, 0x746d4946c0e9F43F4Dee607b0eF1fA1c3318585733ff6000526015600bf30000)

            for {let i := div(value, 32)} i {i := sub(i, 1)} {
                pop(create2(0, 0, 30, add(offset, 0))) pop(create2(0, 0, 30, add(offset, 1)))
                pop(create2(0, 0, 30, add(offset, 2))) pop(create2(0, 0, 30, add(offset, 3)))
                pop(create2(0, 0, 30, add(offset, 4))) pop(create2(0, 0, 30, add(offset, 5)))
                pop(create2(0, 0, 30, add(offset, 6))) pop(create2(0, 0, 30, add(offset, 7)))
                pop(create2(0, 0, 30, add(offset, 8))) pop(create2(0, 0, 30, add(offset, 9)))
                pop(create2(0, 0, 30, add(offset, 10))) pop(create2(0, 0, 30, add(offset, 11)))
                pop(create2(0, 0, 30, add(offset, 12))) pop(create2(0, 0, 30, add(offset, 13)))
                pop(create2(0, 0, 30, add(offset, 14))) pop(create2(0, 0, 30, add(offset, 15)))
                pop(create2(0, 0, 30, add(offset, 16))) pop(create2(0, 0, 30, add(offset, 17)))
                pop(create2(0, 0, 30, add(offset, 18))) pop(create2(0, 0, 30, add(offset, 19)))
                pop(create2(0, 0, 30, add(offset, 20))) pop(create2(0, 0, 30, add(offset, 21)))
                pop(create2(0, 0, 30, add(offset, 22))) pop(create2(0, 0, 30, add(offset, 23)))
                pop(create2(0, 0, 30, add(offset, 24))) pop(create2(0, 0, 30, add(offset, 25)))
                pop(create2(0, 0, 30, add(offset, 26))) pop(create2(0, 0, 30, add(offset, 27)))
                pop(create2(0, 0, 30, add(offset, 28))) pop(create2(0, 0, 30, add(offset, 29)))
                pop(create2(0, 0, 30, add(offset, 30))) pop(create2(0, 0, 30, add(offset, 31)))
                offset := add(offset, 32)
            }

            for {let i := and(value, 0x1F)} i {i := sub(i, 1)} {
                pop(create2(0, 0, 30, offset))
                offset := add(offset, 1)
            }
        }

        _mint(msg.sender, value);
        totalMinted = offset;
    }

    function computeAddress2(uint256 salt) public view returns (address) {
        bytes32 _data = keccak256(
            abi.encodePacked(bytes1(0xff), address(this), salt, bytes32(0x3c1644c68e5d6cb380c36d1bf847fdbc0c7ac28030025a2fc5e63cce23c16348))
        );
        return address(uint256(_data));
    }

    function _destroyChildren(uint256 value) internal {
        uint256 _totalBurned = totalBurned;
        for (uint256 i = 0; i < value; i++) {
            computeAddress2(_totalBurned + i).call("");
        }
        totalBurned = _totalBurned + value;
    }

    function free(uint256 value) public returns (uint256)  {
        _burn(msg.sender, value);
        _destroyChildren(value);
        return value;
    }

    function freeUpTo(uint256 value) public returns (uint256) {
        return free(Math.min(value, balanceOf(msg.sender)));
    }

    function freeFrom(address from, uint256 value) public returns (uint256) {
        _burnFrom(from, value);
        _destroyChildren(value);
        return value;
    }

    function freeFromUpTo(address from, uint256 value) public returns (uint256) {
        return freeFrom(from, Math.min(Math.min(value, balanceOf(from)), allowance(from, msg.sender)));
    }
}