// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract GEICO is IERC20 {
    string public constant name = "GEICO";
    string public constant symbol = "$GEICO";
    uint8 public constant decimals = 18;
    uint256 private _totalSupply = 504 * 10**12 * 10**decimals;

    address public owner = 0x935e844af8254112183e27fee3b7d4cee972a858;

    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;

    constructor() {
        _balances[owner] = _totalSupply;
        emit Transfer(address(0), owner, _totalSupply);
    }

    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function allowance(address _owner, address spender) public view override returns (uint256) {
        return _allowances[_owner][spender];
    }

    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] - amount);
        return true;
    }

    function burn(uint256 amount) public {
        require(_balances[msg.sender] >= amount, "Insufficient balance to burn");
        _balances[msg.sender] -= amount;
        _totalSupply -= amount;
        emit Transfer(msg.sender, address(0), amount);
    }

    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "Transfer from the zero address");
        require(recipient != address(0), "Transfer to the zero address");
        _balances[sender] -= amount;
        _balances[recipient] += amount;
        emit Transfer(sender, recipient, amount);
    }

    function _approve(address _owner, address spender, uint256 amount) internal {
        require(_owner != address(0), "Approve from the zero address");
        require(spender != address(0), "Approve to the zero address");
        _allowances[_owner][spender] = amount;
        emit Approval(_owner, spender, amount);
    }
}