using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var a="rahul";

        var b ="abc";

        var c="DEF";

        var d="XYZ";

        string z ="start {0} My test {1} {2 End file";

        Console.WriteLine(String.Format(z,a,b,c,d));

    }

}