Kobus is on his way to a secret underground private club but does not know the password to get in. He waits by the door and a member knocks, the doorman says twelve, the member answers six, Another member arrives, the doorman says six the member answers three. Seeing enough and confident he can get in he knocks on the door, doorman says ten and Kobus answers five, he was not let in. What should have been Kobus's answer?