The elected student union members, need seven election commissioner, try design votes statistics system, statistics and output total valid votes ticket, every vote the most optional seven members, more than 7 for the devil; Reading a person votes, votes in the first seven when number and each candidate's votes; Vote valid votes more than half of the candidates, : a round of elections, for the selected; If less than 7 votes more than half, then announced the list has been elected, but not more than half of people in the remaining places, until an election is completed, try to draw N S diagram of the system and the PAD,