diff --git a/cv8/program.c b/cv8/program.c
index a83278c..d2cfea6 100644
--- a/cv8/program.c
+++ b/cv8/program.c
@@ -139,7 +139,8 @@ int main() {
         return 1;
     }
 
-    knowledge_system(root);
+    int flag = 0;
+    knowledge_system(root, &flag);
 
     destroy_tree(root);