diff --git a/ex01/RPN.cpp b/ex01/RPN.cpp
index 93851c0..974eb2d 100644
--- a/ex01/RPN.cpp
+++ b/ex01/RPN.cpp
@@ -6,7 +6,7 @@
 /*   By: adjoly <adjoly@student.42angouleme.fr>     +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2025/06/03 12:07:59 by adjoly            #+#    #+#             */
-/*   Updated: 2025/06/03 15:56:22 by adjoly           ###   ########.fr       */
+/*   Updated: 2025/07/03 14:15:57 by adjoly           ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -18,7 +18,7 @@
 #include <stdexcept>
 
 int add(int first, int second) { return first + second; }
-int subst(int first, int second) { return first + second; }
+int subst(int first, int second) { return first - second; }
 int mult(int first, int second) { return first * second; }
 int div(int first, int second) {
 	if (second == 0)