using System;

namespace Shapes
{
    abstract public class Shape
    {
        protected double area;
        protected string name;
        protected Shape(string name)
        {
            this.name = name;
        }
        public abstract double Area();
    }
    public class Square : Shape
    {
        public Square(int a, string name) : base(name)
        {
            area = a * a;
        }
        public override double Area()
        {
            return area;
        }
    }
    public class Circle : Shape
    {
        public Circle(int r, string name) : base(name)
        {
            this.area = Math.PI * r * r;
        }
        public override double Area()
        {
            return area;
        }
    }
    public class Rectangle : Shape
    {
        public Rectangle(int a, int b, string name) : base(name)
        {
            this.name = name;
            this.area = a * b;
        }
        public override double Area()
        {
            return area;
        }
    }

    public class ShapesCollection
    {
        Shape shape;
        string name;
        public ShapesCollection(string name, Shape shape)
        {
            this.shape = shape;
            this.name = name;
        }
        public override string ToString()
        {
            return name + "Area = " + shape.Area().ToString();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            ShapesCollection[] shapes = new ShapesCollection[3]
            {
                new ShapesCollection("Square", new Square(5, "Square")),
                new ShapesCollection("Circle", new Circle(3, "Circle")),
                new ShapesCollection("Rectangle", new Rectangle(4, 5, "Rectangle"))
            };
            System.Console.WriteLine("Shapes Collection");
            foreach (ShapesCollection s in shapes)
            {
                System.Console.WriteLine(s);
            }
        }
    }
}