- Time limit: 1.00 s
- Memory limit: 512 MB
Input
The first input line has an integer $n$: the length of the final string.
The second line has a string of length $m$.
Output
Print the number of strings modulo $10^9+7$.
Constraints
- $1 \le n \le 1000$
- $1 \le m \le 100$
Input:
6
ABCDB
Output:
52
Explanation: The final string will be of the form ABCDB$x$ or $x$ABCDB where $x$ is any character between A–Z.