Good Subsequences

Count the non-empty subsequences in which every character that appears has the same frequency, modulo 1,000,000,007. Choosing the same character from different indices gives different subsequences.

The standard input/output format and any supplementary ranges on this site are as defined in this problem statement.

输入格式

One line containing word, consisting only of lowercase English letters; this site adds 1≤|word|≤200000 to fill in the length upper bound the original problem did not give.

输出格式

Output the number of qualifying non-empty subsequences modulo 1,000,000,007.

样例 1

输入：

abca

输出：

12

样例 2

输入：

abcd

输出：

15

样例 3

输入：

aaa

输出：

7