#700. Palindromic Equivalence

Palindromic Equivalence

Description

给出一个由小写字母组成的字符串S,问有多少由小写字母 构成的字条串S',满足 1:|S|'=|S| 2:S'[L..R]是回文串,当且仅当S[L..R]是回文串

Format

Input

一个字符串S,长度<=10^6

Output

输出答案Mod10^9+7

Samples

abba
650
Only words of the form xyyx are palindromically equivalent to abba, where x and y are distinct letters.
The English alphabet contains 26 letters, consequently there are 26*25=650 such words in total.