Kerry,during a recent trip to Afghanistan and Pakistan, is credited with playing a key role in convincing Afghan President Hamid Karzai to enter a run-off election, following wide-spread corruption that tainted the initial contest in August.

VOA: standard.2009.10.26

assuming I counted right, suppose that the following candidates enter.

假设我数对了,假设以下候选人参选

耶鲁公开课 - 博弈论课程节选