using System;

public class Program

{

    public static void Main()

    {

        int first = 1;

        int second = 2;

        Swap(ref first, ref second);

        Console.WriteLine($"{first},{second}");

    }

    public static void Swap(ref int x, ref int y)

    {

        int temp = x;

        x=y;

        y=temp;

    }

}