diff --git a/app/src/main/java/sudoku/solver/Solver.java b/app/src/main/java/sudoku/solver/Solver.java
index 3dd991a..bb96a97 100644
--- a/app/src/main/java/sudoku/solver/Solver.java
+++ b/app/src/main/java/sudoku/solver/Solver.java
@@ -68,9 +68,11 @@ public class Solver {
      * @param doku MultiDoku, MultiDoku dont on veut le nombre de solutions.
      * @return int, nombre de solutions possibles.
      */
-    public static int countSolution(MultiDoku doku) {
+    public static int countSolution(MultiDoku oldDoku) {
         int result = 0;
 
+        MultiDoku doku = oldDoku.clone();
+
         if (doku.isValid()) {
             return 1;
         }