using System;

//If any class inherits from class “B” then method – “First” will not be overridable as this method is sealed in class B.

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

       class A

{

 protected virtual void First() { }

 protected virtual void Second() { }

}

class B : A

{

 sealed protected override void First() {}

 protected override void Second() { }

}

        class c:B{

            protected override void First(){}

        }

    }

}