MAYBE
47.85/17.90	MAYBE
47.85/17.90	
47.85/17.90	Problem:
47.85/17.90	 a(x1) -> x1
47.85/17.90	 a(a(b(x1))) -> b(b(a(a(x1))))
47.85/17.90	 c(b(x1)) -> c(a(x1))
47.85/17.90	
47.85/17.90	Proof:
47.85/17.90	 Open
47.85/17.92	EOF