using System;

public class Program

{

    public static void Main()

    {

         int  a=5, b=10;            

       Console.WriteLine("Before swap a= "+a+" b= "+b);    

       a=a+b; //a=15 (5+10)      

       b=a-b; //b=5 (15-10)      

       a=a-b; //a=10 (15-5)   

       Console.Write("After swap a= "+a+" b= "+b); 

    }

}