**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 pattern of length $m$.

**Output**

Print the number of strings modulo $10^9+7$.

**Constraints**

- $1 \le n \le 1000$

- $1 \le m \le 100$

**Example**

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.