class A {
  int i = 10;

  int foo() { 
    return i;
  }

}


class B extends A {
  int i = 20;

  int foo() {
    return -i;
  }
}

class TestHello {
  public static void main(String argv[]) {
    B b = new B();
    System.out.println(b.i);
    System.out.println(b.foo());

    A a = (A) b;
    System.out.println(a.i);
    System.out.println(a.foo());
  }
}