diff --git a/09/part2.pl b/09/part2.pl
index 9a06c70..f7d45e9 100644
--- a/09/part2.pl
+++ b/09/part2.pl
@@ -1,12 +1,11 @@
 start :-
     input(Input),
-    findall(P, (member(L, Input), predict(L, P)), Ps),
+    maplist(predict, Input, Ps),
     sum_list(Ps, Answer),
     writef('Answer=%t\n', [Answer]).
 
 predict(L, 0) :- maplist(=:=(0), L), !.
 predict(L, X) :-
-    L = [L1 | CdrL],
     foldl([Li1, Li2, C, D]>>(Li2 is Li1 - C, D = Li1), L, [_ | NewL], 0, _),
     predict(NewL, SubX),
-    X is L1 - SubX.
+    L = [L1 | _], X is L1 - SubX.