diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index 2436fb8..0a11c7d 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -251,4 +251,6 @@ let assos k l =
 		invalid_arg "k not natural"
 	else 
 	match l with
-		| e::t -> 
+		|  -> failwith "not found"
+		| (k,y)::t -> y
+		| _ -> assos k t