True, a pre-

Algorithm taking tests / exams on a "13th ticket».

1. To learn the answer to the ticket at number 13.
 2. Before "event" something "does not like" the teacher (get nasty, ask a stupid question, and so on. N.), In order to discourage the latter any self pity.
 3. Go to the audience first. Next is taken arbitrary ticket from a handful of mid and doing crazy eyes with lamentations such as "THIRTEEN AGAIN !!!, Why am I so unlucky ?! WHY ?? ... "ticket is thrust back into a pile on the table, and a handful of this nervously agitated. The reaction of the teacher is obvious:
 - Look, look, Ivanov, his thirteenth TICKET!