：用一个变量记录最近一次按动的是左键还是右键，如果连续两次都是左键或者都是右键，则忽略后一次，只有当交替按下了左键和右键时，才计算一个轮次，用一个变量记录轮次的个数。设定五秒钟为一个测试时间，当时间到时，则显示出在这段时间内轮次的个数以及不合法按键的次数。

-: Use a variable record is the most recent press left or right, if two consecutive left or both are right, ignore the latter, only when you press the left and right turn only when computing a round times, recorded with a variable number of rounds. Set a testing time for five seconds, when the time, then the show during this period the number of rounds and the number of illegal keys.