197.79/50.49	MAYBE
197.79/50.49	
197.79/50.49	Problem:
197.79/50.49	 b(b(b(b(x1)))) -> a(a(b(b(x1))))
197.79/50.49	 a(a(a(a(x1)))) -> b(a(a(a(x1))))
197.79/50.49	 a(b(a(b(x1)))) -> b(b(a(a(x1))))
197.79/50.49	
197.79/50.49	Proof:
197.79/50.49	 Open
197.79/50.49	EOF