编写一个程序要求用户输入一段文字，然后按照每个单词的开头字母对这段文字分类统计单词的数量并排序输出。（sjtu 二专 作业2）-Write a program that requires the user to input a paragraph of text, and then follow the first letter of each word on the statistics of this text and sort out the number of words. (Sjtu two special operation 2)