This is a tricky riddle...
Queen Elizabeth organized a royal party.
To Avoid uninvited guest royal family set a password. Wayne (an uninvited person) plan to enter the party. He stand nearby the door.
First guest comes, the security person said 'twelve' and guest replied with six. Second guest comes , the security person said 'six' and guest replied with 'three'.
Wayne thought is enough and he walked to the entry point. The security person said 'eight' , Wayne replied smilingly 'four'. He was immediately thrown out of the party.
Why could he possibly be thrown out if he answered correct?