using System;

namespace inherit
{
    class Program
    {
        static void Main(string[] args)
        {
            Rectangle a = new Rectangle();
            Rectangle b = new Rectangle(2, 3);
            Brick c = new Brick();
            Brick d = new Brick(2, 3, 1);

            Console.WriteLine("the area of a = {0}", a.area());
            Console.WriteLine("the area of b = {0}", b.area());
            Console.WriteLine("the area of c = {0}", c.area());
            Console.WriteLine("the area of d = {0}", d.area());
            Console.WriteLine("the volume of c = {0}", c.volume());
            Console.WriteLine("the volume of d = {0}", d.volume());

        }
    }

    class Rectangle
    {
        protected int width;
        protected int height;

        public Rectangle()
        {
            width = 1;
            height = 1;
        }

        public Rectangle(int side)
        {
            this.width = side;
            this.height = side;
        }

        public Rectangle(int width, int height)
        {
            this.width = width;
            this.height = height;
        }

        public int area()
        {
            return width * height;
        }

    }

    class Brick : Rectangle
    {
        protected int thickness;
        public Brick()
        {
            width = 1;
            height = 1;
            thickness = 1;
        }

        public Brick(int side)
        {
            this.width = side;
            this.height = side;
            this.thickness = side;
        }

        public Brick(int width, int height, int thickness)
        {
            this.width = width;
            this.height = height;
            this.thickness = thickness;
        }

        public int volume()
        {
            return width * height * thickness;
        }
    }

}