using System;

public class Program

{

    public static void Main()

    {

        Shape a = new Shape();

        Shape b = new Circle();

        Shape c = new Rectangle();

        a.Draw();

        b.Draw();

        c.Draw();

        Circle d = new Circle();

        d.Draw();

    }

    public class Shape

    {

        public virtual void Draw()

        {

            Console.WriteLine("Base Draw");

        }

    }

    public class Circle:Shape

    {

        public override void Draw()

        {

            Console.WriteLine("Draw circle");

        }

    }

    public class Rectangle:Shape

    {

        public override void Draw()

        {

            Console.WriteLine("Draw rectangle");

        }

    }

}