4.46/4.24	MAYBE
4.46/4.25	
4.46/4.25	Problem:
4.46/4.25	 a() -> b()
4.46/4.25	 f(x,a()) -> f(b(),b())
4.46/4.25	 f(b(),x) -> f(b(),b())
4.46/4.25	 f(f(x,y),z) -> f(b(),b())
4.46/4.25	
4.46/4.25	Proof:
4.46/4.25	 Open
4.46/4.25	EOF