diff --git a/Algo/Courses/Chapter 7 - High Order (exercises).md b/Algo/Courses/Chapter 7 - High Order (exercises).md
index 2fe2e51..4cbaf30 100644
--- a/Algo/Courses/Chapter 7 - High Order (exercises).md	
+++ b/Algo/Courses/Chapter 7 - High Order (exercises).md	
@@ -78,7 +78,7 @@ val partition : ('a -> bool) -> 'a list -> 'a list * 'a list = <fun>
 ```
 
 ## Ex 2.7
-```
+```Ocaml
 # let less2 p k l1 l2 =
 	if k < 0 then invalid_arg "k needs to be positive" else
 		let rec less p k l1 l2 acc = match (l1, l2) with 
@@ -88,3 +88,5 @@ val partition : ('a -> bool) -> 'a list -> 'a list * 'a list = <fun>
 		in less p k l1 l2 0;;
 val less2 : ('a -> 'b -> bool) -> int -> 'a list -> 'b list -> bool = <fun>
 ```
+## Ex 3.1
+```Ocaml