class Two {
   public static void main(String[] args) {
     Shape[] a = new Shape[2];
     a[0] = new Circle(0.5);
     a[1] = new Rectangle(12, 30);
     for (int i = 0; i < a.length; i++)
      System.out.println(a[i].area());
   }
}
interface Shape {
   double area();
}
class Circle implements Shape {
   double radius;
   Circle(double radius) {
     this.radius = radius;
   }
   public double area() {
     return Math.PI * Math.pow(this.radius, 2);
   }
}
class Rectangle implements Shape {
   double width, height;
   Rectangle(double width, double height) {
     this.width = width;
     this.height = height;
   }
   public double area() { return this.height * this.width; }
}

class One {
   public static void main(String[] args) {
     for (int i = 0; i < args.length; i = i + 1) {
       System.out.println(args[i]);
     }
   }
}