class A {}
class B extends A {}
class C extends A {}
class D extends C {}

class TrueOrFalse {
	public static void main(String[] args) {
		A a = new A();
		B b = new B();
		C c = new C();
		D d = new D();
		A e = new D();
		A f = new B();

                //Tilfelle 1
                B ab = (B) a;

                //Tilfelle 2
                if( e instanceof B ){
                    B eb = (B) e;
                }
        
                //Tilfelle 3
                D ed = (D) e;

                //Tilfelle 4
                if( e instanceof D ){
                    D ed = (D) e;
                }

                //Tilfelle 5
                B fb = (B) f; 

                //Tilfelle 6
                C ec = (C) e; 
	        }
}