Update app.py

app.py

@@ -52,7 +52,7 @@ def load_default_pdf():
         llm = ChatOpenAI(
             openai_api_key=OPENROUTER_API_KEY,
             openai_api_base="https://openrouter.ai/api/v1",
-            model="openchat/openchat-3.5-0106:free",  #mistralai/mistral-7b-instruct:free
+            model="mistralai/mistral-7b-instruct:free",  #mistralai/mistral-7b-instruct:free
             temperature=0.3
         )