using System;

public class Program

{

    public static void Main()

    {

        swap();

        Console.WriteLine("Hello World");

    }

    public static void swap()

    {

        int a = 2;

        int b = 3;

        Console.WriteLine(string.Format("Before swap: a: {0} and b: {1}", a, b));

        a = a+b;

        b = a-b;

        a = a-b;

        Console.WriteLine(string.Format("After swap: a: {0} and b: {1}", a, b));

​

    }

}