Store a number and retreive its value

HelloWorld.sol

//SPDX-License-Identifier: MIT

pragma solidity 0.8.7;

contract HelloWorld {
    
    // Declaring a global variable that stores the number
    uint myNumber;

  /** @dev Store a given number into a variable
    * Input - unsigned integer
    * @param num value to myNumber 
    */
    function storeNumber(uint num) public {
        myNumber = num;
    }

  /** @dev Return the stored number
    * Output - unsigned integer
    * @return value of myNumber
    */
    function retrieveNumber() public view returns(uint) {
        return myNumber;
    }

} //closing contract 'HelloWorld'