Update app.py

app.py

@@ -28,6 +28,7 @@ with gr.Blocks() as demo:
     with gr.Tab("Upload PDF & TXT"): 
         docs_input = gr.File(file_count="single", file_types=[".pdf"])
         tb_tokenCount = gr.Textbox(label='Number of tokens')
+        docs_input.upload(count_tokens_in_file,inputs=[docs_input],outputs=[tb_tokenCount])
         btn_count = gr.Button("Count token")
         btn_count.click(count_tokens_in_file,inputs=[docs_input],outputs=[tb_tokenCount])