using System;

​

public class Program

{

    public static void Main()

    {

        B testB = new B();

        testB.Test();

    }

}

​

public class A

{

    public A()

    {

    }

​

    public virtual void Test()

    {

        Console.WriteLine("I am A");

    }

}

​

public class B : A

{

    public B()

    {

    }

​

    public override void Test()

    {

      Console.WriteLine("I am B");

    }

}