Write a program swapping two numbers without using third variable

class Program

    {

        static void Main(string[] args)

        {

            int a, b;

            Console.WriteLine("Enter the first number");

            a = int.Parse(Console.ReadLine());

            Console.WriteLine("Enter the second number");

            b = int.Parse(Console.ReadLine());

            a = a + b;

            b = a - b;

            a = a - b;

            Console.WriteLine("After swaping");

            Console.WriteLine("The first number is:{0}", a);

            Console.WriteLine("The second number is:{0}", b);

            Console.ReadLine();

        }

    }

output: