diff --git a/Algo/Séminaire/Exercices seminaire.md b/Algo/Séminaire/Exercices seminaire.md
index 0299035..76ac459 100644
--- a/Algo/Séminaire/Exercices seminaire.md	
+++ b/Algo/Séminaire/Exercices seminaire.md	
@@ -444,14 +444,12 @@ $$
 $$
 = O(log(n))
 $$
-## 4.12 - Prime number
+##  Exercise 4.12 - Prime number
 ```Ocaml
 let prime n =
 	if n < 1 then
 		invalid_args "n should not be inferior to zero"
+	else if n mod 2 = 0 then
+		false
 	else
-		let rec p n = 
-			if n = 0 then
-				1
-			else
-	
\ No newline at end of file
+		
\ No newline at end of file