Calculate the number of ways you can reorder the characters of a string so that no two adjacent characters are the same.
For example, the answer for aabc is $6$ , because the possible orders are abac , abca , acab , acba , baca , and caba .
The only input line has a string that consists of $n$ characters between a – z .
Print an integer: the answer modulo $10^9+7$ .