277.88/50.93	MAYBE
277.94/50.93	
277.94/50.93	Problem:
277.94/50.93	 a(b(b(b(x1)))) -> b(a(b(a(x1))))
277.94/50.93	 a(b(b(b(x1)))) -> a(a(a(b(x1))))
277.94/50.93	 b(a(a(b(x1)))) -> b(b(a(b(x1))))
277.94/50.93	 b(a(a(a(x1)))) -> a(a(a(b(x1))))
277.94/50.93	
277.94/50.93	Proof:
277.94/50.93	 Open
277.94/50.93	EOF