Problem Statement

How many strings can be obtained by applying the following operation on a string S exactly K times: "choose one lowercase English letter and insert it somewhere"?
The answer can be enormous, so print it modulo (10^9+7).

Input

Input is given from Standard Input in the following format:
K
S

Output

Print the number of strings satisfying the condition, modulo (10^9+7).

Constraints

• K is an integer between 1 and 10^6 (inclusive).
• S is a string of length between 1 and 10^6 (inclusive) consisting of lowercase English letters.

Sample Input 1

5
oof

Sample Output 1

575111451

For example, we can obtain proofend, moonwolf, and onionpuf, while we cannot obtain oofsix, oofelevennn, voxafolt, or fooooooo.

Sample Input 2

37564
whydidyoudesertme

Sample Output 2

318008117

见题面 Input 部分

见题面 Output 部分