using System; 
  
 // کلاس پایه برای اشکال هندسی 
 public abstract class Shape 
 { 
     public abstract double Area(); 
     public abstract double Perimeter(); 
 } 
  
 // کلاس مربع 
 public class Square : Shape 
 { 
     public double Side { get; set; } 
  
     public Square(double side) 
     { 
     Side = side; 
     } 
  
     public override double Area() 
     { 
     return Side * Side; 
     } 
  
     public override double Perimeter() 
     { 
     return 4 * Side; 
     } 
 } 
  
 // کلاس دایره 
 public class Circle : Shape 
 { 
     public double Radius { get; set; } 
  
     public Circle(double radius) 
     { 
     Radius = radius; 
     } 
  
     public override double Area() 
     { 
     return Math.PI * Radius * Radius; 
     } 
  
     public override double Perimeter() 
     { 
     return 2 * Math.PI * Radius; 
     } 
 } 
  
 // کلاس مستطیل 
 public class Rectangle : Shape 
 { 
     public double Width { get; set; } 
     public double Height { get; set; } 
  
     public Rectangle(double width, double height) 
     { 
     Width = width; 
     Height = height; 
     } 
  
     public override double Area() 
     { 
     return Width * Height; 
     } 
  
     public override double Perimeter() 
     { 
     return 2 * (Width + Height); 
     } 
 } 
  
 class Program 
 { 
     static void Main(string[] args) 
     { 
     Square square = new Square(5); 
     Console.WriteLine($"مساحت مربع: {square.Area()}"); 
     Console.WriteLine($"محیط مربع: {square.Perimeter()}"); 
  
     Circle circle = new Circle(3); 
     Console.WriteLine($"مساحت دایره: {circle.Area()}"); 
     Console.WriteLine($"محیط دایره: {circle.Perimeter()}"); 
  
     Rectangle rectangle = new Rectangle(4, 6); 
     Console.WriteLine($"مساحت مستطیل: {rectangle.Area()}"); 
     Console.WriteLine($"محیط مستطیل: {rectangle.Perimeter()}"); 
     } 
 }