Code not working

Hrithik Singh <[email protected]> Mon, 10 May 2021 18:10:39 +0530

Newsgroups	gmane.comp.gnu.prolog.general
Message-ID	<CAKDCGbA=7yaM2+sKZKBJJGpT5dVJuN5DeyM+_XKErjtKt7bPuQ@mail.gmail.com>

I have executed the following code :
bfs(X,Y,P)
 bfs_a(Y,[n(X,[])],R),
 reverse(R,P).

But it is showing an error.... Can you please send the right code to help
me.