- Time limit: 1.00 s
- Memory limit: 512 MB
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
The only input line has a string that consists of n characters between
Print an integer: the answer modulo 10^9+7.
- 1 \le n \le 5000