MAYBE
24.70/10.18	MAYBE
24.70/10.18	
24.70/10.18	Problem:
24.70/10.18	 a(x1) -> x1
24.70/10.18	 a(b(x1)) -> b(b(a(x1)))
24.70/10.18	 b(x1) -> c(a(c(x1)))
24.70/10.18	 c(c(x1)) -> x1
24.70/10.18	
24.70/10.18	Proof:
24.70/10.18	 Open
24.70/10.19	EOF