diff --git a/CTAssetsPickerController/CTAssetsGridSelectedView.m b/CTAssetsPickerController/CTAssetsGridSelectedView.m
index d3fcca1f..2d5cc471 100644
--- a/CTAssetsPickerController/CTAssetsGridSelectedView.m
+++ b/CTAssetsPickerController/CTAssetsGridSelectedView.m
@@ -155,7 +155,7 @@ - (void)setShowsSelectionIndex:(BOOL)showsSelectionIndex
 - (void)setSelectionIndex:(NSUInteger)selectionIndex;
 {
     _selectionIndex = selectionIndex;
-    self.selectionIndexLabel.text = [NSString stringWithFormat:@"%lu", (unsigned long)selectionIndex + 1];
+    self.selectionIndexLabel.text = [NSString stringWithFormat:@"%lu", (unsigned long)(selectionIndex + 1)];
 }