using System;

​

//this is class

public class Program

{

    //this is main method, which is also static

    public static void Main()

    {

        //static method

        AddTwoNumber();

    }

    //we have used static keyword, so we don't need to class it's class object

    public static void AddTwoNumber()

    {

         int a=10, b=20;        

         int c= a+b;

         Console.WriteLine("Sum ="+c);  

    }

}