class List<A> { A a = null; } class AbstractList<A> extends List<A> { A a = null; } class Vektor<A> extends AbstractList<A> { A a = null; } class Stack<A> extends Vektor<A> { A a = null; } class Objekt { } class Int { } class Paar<A, B> { A a = null; B b = null; } class otth16 { }