diff --git a/image_ref/dataset_ref.py b/image_ref/dataset_ref.py
index 676ed89b9e3d36b6e3839052aa6e4409c9bee076..37054d71a490ca9d2702b791f759539d4e4b92b1 100644
--- a/image_ref/dataset_ref.py
+++ b/image_ref/dataset_ref.py
@@ -133,7 +133,7 @@ class ImageFolderDuo(data.Dataset):
             if i < self.positive_prop:
                 label_ref = target
             else :
-                l = np.arange(0,len(self.classes)-1,dtype=int).tolist()
+                l = np.arange(0,len(self.classes),dtype=int).tolist()
                 l.remove(target)
                 label_ref = np.random.choice(l)
         else :