diff --git a/ai/views/oj.py b/ai/views/oj.py
index 11f987f..ca0c8db 100644
--- a/ai/views/oj.py
+++ b/ai/views/oj.py
@@ -227,6 +227,7 @@ class AIDetailDataAPI(APIView):
                     "rank": rank,
                     "ac_count": len(ranking_list),
                     "grade": get_grade(rank, len(ranking_list)),
+                    "difficulty": get_difficulty(problem.difficulty),
                 }
             )