一列火车要将n节车厢分别送往n个车站车站按1~n的次序编号，火车按照n, n-1,…, 1的编号次序经过车站。假设车厢的编号就是其目的地车站的编号。

-A train to n cars n stations were sent to stations by 1 ~ n the order of numbers, the train in accordance with n, n-1, ..., 1 after the station number sequence. Suppose car number is its destination station number.