pragma solidity ^0.8.0;

contract StakingContract {
  mapping(address => uint256) public balances;

  function stake() public payable {
    balances[msg.sender] += msg.value;
  }

  function withdraw() public {
    uint256 amount = balances[msg.sender];
    require(amount > 0, "No balance to withdraw");
    balances[msg.sender] = 0;
    (bool success, ) = msg.sender.call{value: amount}("");
    require(success, "Withdraw failed");
  }
}