diff --git a/contents/_components/QuestionGroups.json b/contents/_components/QuestionGroups.json
index ac24f284..1e1c5b5f 100644
--- a/contents/_components/QuestionGroups.json
+++ b/contents/_components/QuestionGroups.json
@@ -327,7 +327,7 @@
       "url": "https://leetcode.com/problems/min-stack",
       "duration": 20,
       "epi": 0,
-      "difficulty": "Easy",
+      "difficulty": "Medium",
       "premium": false,
       "frequency": 0.892,
       "likes": 0.588,