Update app.py

app.py

@@ -65,7 +65,7 @@ def generate_questions_with_retry(knowledge_material, question_type, cognitive_l
     while retries < max_retries:
         try:
             response = client.chat.completions.create(
-                model="gpt-4o mini",  # or your preferred model
+                model="gpt-4o-mini",  # or your preferred model
                 messages=[
                     {"role": "system", "content": "You are a helpful assistant for generating exam questions."},
                     {"role": "user", "content": prompt}