Li Si An Birthday as a Passcode

How can all these magic cards be rejected?

Has Su Yu replaced the door panel?

"Master Su seems to have changed his door panel settings so that they don't accept the pass card. Madam, you may be able to use the password."

Passwords? What's the password? Does Li Si An even know the password?

Li Si An glanced at the number pads on the door panel. She had no idea about Su Yu's study room password. All this time Li Si An had always sneaked in with a pass card so she had no idea what the password was.

What number should Li Si An press? She didn't want any push of a button to try. Li Si An was a hostess who should know about small things like this.

Too bad there's no buzzer or intercom button there. Su Yu did not install that feature so that no one would disturb him while he was in the study room. If there is Li Si An only need to shout to get out of the room.