An accountant without the sense of humour.
Because all the other fore letter words were taken (Thanks to... this now makes sense...)
Prism (Note: I made this joke up. Sorry if this little note refracts from the humour.)
He worked is out with a pencil.
It's 9.18 am and 12 seconds no wait - 13 seconds no wait - 14 seconds no wait......
Invite an accountant.