Alan wants to enter into an exclusive Accesso Club event but the entry requires a password he doesn’t know. So, he waits nearby and listens to the conversations happening around him. As a club member comes to the door, the security officer says, “Twelve”. She replies, “Six” and gets in. Another member comes to the door. The security officer says, “Six” and the man replies, “Three” and gets in. Alan thinks that he understands the pattern and walks up to the door. The security officer says, “Ten” and Alan replies, “Five” but the security guard doesn’t let him in.
Question: What’s the password?