diff --git a/SortingAlgorithm/bitImageSort.py b/SortingAlgorithm/bitImageSort.py
index 0c53313..1d0000c 100644
--- a/SortingAlgorithm/bitImageSort.py
+++ b/SortingAlgorithm/bitImageSort.py
@@ -10,7 +10,7 @@
 for i in range(0, 10000000):
     indexList.append(0)
 
-
+# use +1 can make sure we won't miss some equals number.
 for num in inputList:
     indexList[num] += 1