diff --git a/photo_review/auto_photo_review.py b/photo_review/auto_photo_review.py
index 014ab10..78e764b 100644
--- a/photo_review/auto_photo_review.py
+++ b/photo_review/auto_photo_review.py
@@ -583,7 +583,7 @@ def photo_review(pk_phhd, name):
         cost_missing_page = {}
         if cost_data.get('page_nums'):
             page_nums = cost_data['page_nums'].split(',')
-            required_set = set(range(1, cost_data['page_count'] + 1))
+            required_set = set(str(i) for i in range(1, cost_data['page_count'] + 1))
             page_set = set(page_nums)
             cost_missing_page = required_set - page_set
         if cost_missing_page: