using System;

public class Program

{

    public static void Main()

    {

        A a = new A();

        B b = new B();

    }

    public class A

    {

        public virtual void Show()

        {   

            Console.WriteLine("A.Show()");

        }

    }

    public class B : A

    {

        public override void Show()

        {   

            Console.WriteLine("B.Show()");

        }

    }

}