Update app.py

app.py

@@ -302,7 +302,7 @@ async def grade_papers_concurrently(
     total_files = len(file_paths)
 
     # Use a ThreadPoolExecutor to run synchronous tasks concurrently
-    with ThreadPoolExecutor(max_workers=2) as executor:
+    with ThreadPoolExecutor(max_workers=1) as executor:
         # Create a future for each file processing task
         loop = asyncio.get_event_loop()
         tasks = [