假设要在足够多的会场里安排一批活动，并希望使用尽可能少的会场。设计一个有效的贪心算法来进行安排。试编程实现对于给定的k个待安排活动，计算使用的最少会场。输入数据中，第一行是k的值，接下来的k行中，每行有2个正整数，分别表示k个待安排活动的开始时间和结束时间，时间以0点开始的分钟计。输出为最少的会场数。-Suppose you want to arrange a number of activities in enough of the hall, and want to use as little as possible venue. Design a greedy algorithm to be arranged. Test programming activities to be arrangements to achieve a given k, calculated using the least venue. The input data, the first line is the value of k, the next k rows, each row has two positive integers, respectively the k be arranged to start time and end time, the time 0:00 minutes. The output of the minimum number of venue.