Ignatius最近遇到一个难题,老师交给他很多单词，现在老师要他统计出以某个字符串为前缀的单词数量......
FJ is about to take his N (1 ≤ N ≤ 2,000) cows to the annual"Farmer of the Year" competition...
Assume the coasting is an infinite straight line. Land is in one side of coasting, sea in the other...