Class Test

Counter.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;

contract Counter {
    uint256 count;

    uint256 restrictionTime = block.timestamp + 30;

    function add() public {
        require(block.timestamp < restrictionTime, "restriction time reached");
        count++;
    }

    function decrement() public {
        require(block.timestamp < restrictionTime, "restriction time reached");
        count--;
    }

    function showCount() public view returns (uint256) {
        return count;
    }
}