//prints 2 2 2 2 0 1 2 2 2 0 1 1 2 2 0 1 1 2 1 0

class C extends Object { }

class D extends Object { }

class C1 extends C {
  nat foo (Object o) {
    if (o instanceof Object) {printNat(1);} else {printNat(2);};
    if (o instanceof C) {printNat(1);} else {printNat(2);};
    if (o instanceof D) {printNat(1);} else {printNat(2);};
    if (o instanceof C1) {printNat(1);} else {printNat(2);};
    printNat(0);
  }
}

main {
  C1 tester;
  tester = new C1();
  tester.foo(null);
  tester.foo(new Object());
  tester.foo(new C());
  tester.foo(new C1());
}