272.67/49.90	MAYBE
272.67/49.90	
272.67/49.90	Problem:
272.67/49.90	 a(b(b(a(x1)))) -> b(b(a(a(x1))))
272.67/49.90	 b(b(b(a(x1)))) -> a(a(a(a(x1))))
272.67/49.90	 a(b(a(a(x1)))) -> b(a(b(b(x1))))
272.67/49.90	
272.67/49.90	Proof:
272.67/49.90	 Open
272.67/49.90	EOF