using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApp3
{
    class Program
    {
        static void function(ref int x) {
            x = x * x;
        }
        static void Main()
        {
            int a = 5;
            int n;
            function(ref a);
            Console.WriteLine(a);
            function(ref a);
            Console.WriteLine(a);
            Console.ReadLine();

        }
    }
}