MAYBE
26.94/10.18	MAYBE
26.94/10.18	
26.94/10.18	Problem:
26.94/10.18	 a(x1) -> x1
26.94/10.18	 a(b(x1)) -> b(b(a(c(x1))))
26.94/10.18	 b(x1) -> a(c(x1))
26.94/10.18	 c(c(x1)) -> x1
26.94/10.18	
26.94/10.18	Proof:
26.94/10.18	 Open
26.94/10.19	EOF