Harvard linguistics professor George Kingsley Zipf (1902-1950) observed that the frequency of the k-th most common word in a text is roughly proportional to 1/k. He justified his observations in a book titled Human behavior and the principle of least effort published in 1949. While Zipf’s rationale has largely been discredited, the principle still holds, and others have afforded it a more sound mathematical ba- sis. You are to find all the words occurring n times in an English text. A word is a sequence of letters. Words are separated by non-letters. Capitalization should be ignored. A word can be of any length that an English word can be. Input Input consists of several test cases. The first line of each case contains a single positive integer n. Several lines of text follow which will contain no more than 10000 words. The text for each case is terminated by a single line containing EndOfText. EndOfText does not appear elsewhere in the input and is not considered a word. Output For each test case, output the words which occur n times in the input text, one word per line, lower case, in alphabetical order. If there are no such words in input, output the following line: There is no such word. Leave a blank line between cases. Sample Input 2 In practice, the difference between theory and practice is always greater than the difference between theory and practice in theory.
Anonymous Man will occasionally stumble over the truth, but most of the time he will pick himself up and continue on. - W. S. L. Churchill EndOfText
2/2 Sample Output between difference in will