程序从文件crossin.txt读入一篇文档。该文档由若干行组成，每行中包含一系列单词。

将输入文档中所有出现的单词及其所在行号输出到文件crossout.txt中。

输出有若干行，每一行都是文档中出现的一个单词。按如下规格输出：

word:line1,line2, … ,lineN-Program read from a document file crossin.txt. The document consists of several lines, each line contains a series of words. The input document where all occurrences of the word and its line number in the output to a file crossout.txt. There are a number of output lines, each line is a word appears in the document. Output specifications as follows: word: line1, line2, ..., lineN