MAYBE
0.08/0.17	MAYBE
0.08/0.17	
0.08/0.17	Problem:
0.08/0.17	 null(nil()) -> true()
0.08/0.17	 null(add(n,x)) -> false()
0.08/0.17	 tail(add(n,x)) -> x
0.08/0.17	 tail(nil()) -> nil()
0.08/0.17	 head(add(n,x)) -> n
0.08/0.17	 app(nil(),y) -> y
0.08/0.17	 app(add(n,x),y) -> add(n,app(x,y))
0.08/0.17	 reverse(nil()) -> nil()
0.08/0.17	 reverse(add(n,x)) -> app(reverse(x),add(n,nil()))
0.08/0.17	 shuffle(x) -> shuff(x,nil())
0.08/0.17	 shuff(x,y) -> if(null(x),x,y,app(y,add(head(x),nil())))
0.08/0.17	 if(true(),x,y,z) -> y
0.08/0.17	 if(false(),x,y,z) -> shuff(reverse(tail(x)),z)
0.08/0.17	
0.08/0.17	Proof:
0.08/0.17	 Open
0.08/0.18	EOF