class Ring {
  double radius1;
  double radius2;
  double pi = 3.14;

  Ring(double r1, double r2) {
    radius1 = r1;
    radius2 = r2;
  }

  double ring1() {
    return pi * Math.pow(radius1, 2);
  }

  double ring2() {
    return pi * Math.pow(radius2, 2);
  }

}

class Circle {
  public static void main(String[] args) {

    Ring testRing = new Ring(7, 5);

    double a = testRing.ring1();
    double b = testRing.ring2();
    double c = a - b;

    System.out.println(a);
    System.out.println(b);
    System.out.println(c);
  }
}