class Main {
public static void main(String[] args) {
System.out.println("Hello World!");
}
}
class A {
public static void main(String[] args){
A c = new C();
A d = new D();
System.out.println(c instanceof A && d instanceof A);
System.out.println(c instanceof C && d instanceof D);
System.out.println(c instanceof D);
System.out.println(d instanceof C);
}
}
// subclassing!
class C extends A { }
class D extends A { }