MAYBE
49.88/18.60	MAYBE
49.88/18.61	
49.88/18.61	Problem:
49.88/18.61	 a(x1) -> x1
49.88/18.61	 a(a(b(x1))) -> b(a(b(a(x1))))
49.88/18.61	 b(b(x1)) -> c(a(x1))
49.88/18.61	
49.88/18.61	Proof:
49.88/18.61	 Open
49.88/18.61	EOF