AT_jag2018summer_day2_h Prefix Suffix Free

[problemUrl]: https://atcoder.jp/contests/jag2018summer-day2/tasks/jag2018summer_day2_h You are given a string $ S $ consisting of lowercase English letters. Count the number of strings $ T $ that satisfies all of the following conditions: - $ T $ is a string of the same length as $ S $, consisting of lowercase English letters. - For all $ K $ ( $ 1\ \leq\ K\ \leq\ |S| $ ), the string formed by the first $ K $ letters of $ S $ does not coincide with the string formed by the last $ K $ letters of $ T $. Since the answer can be very large, find the number modulo $ 10^9+7 $.

Input is given from Standard Input in the following format: > $ S $

Print the number of strings that satisfy the condition, modulo $ 10^9+7 $.

### Constraints - $ 1\ \leq\ |S|\ \leq\ 10^6 $ - $ S $ consists of lowercase English letters. ### Sample Explanation 1 For example, $ T= $ `zz` and `ab` satisfy the condition, but `ba` or `aa` does not.