Update app.py

app.py

@@ -37,7 +37,7 @@ You are a helpful AI assistant named Athspi. When responding:
 """
 
 genai.configure(api_key=os.getenv("GEMINI_API_KEY"))
-model = genai.GenerativeModel('https://tinyurl.com/athspi-spacegemini-1.5-pro', system_instruction=system_instruction)
+model = genai.GenerativeModel('gemini-2.5-flash', system_instruction=system_instruction)
 
 # In-memory session storage
 chat_sessions = {}