public static void main(String[] args) { A a0 = new A(); A a1 = new A(); A a2 = new A(); B b = new B(3); b.addU(a0.buildU(), 0); b.addU(a1.buildU(), 1); b.addU(a2.buildU(), 2); b.showUs(); b.testUs(); b.eraseU(0); b.eraseU(1); b.showUs(); }