diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index 9f31447..88d2734 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -195,4 +195,11 @@ let insert_nth w i list =
 			| (i, e::t) -> e::insrec(i-1, t)
 		in insrec i list;;
 val insert_nth: 'a -> int -> 'a list -> 'a list = <fun>
-	
\ No newline at end of file
+```
+
+## Exercise 3.4
+```
+# let insert_post x y list = match list with
+	| [] -> failwith "list is too large or empty"
+	| e::t -> if e = x then e::y::t else e::insert_post x y (t);;
+val insert_post : 'a -> '
\ No newline at end of file