Rolling Encryption

You have a string of lowercase letters and you want to encrypt it.

The first $k$ letters are written out unchanged. Every letter after the first $k$ is shifted by the most frequent letter among the $k$ letters that sit directly before it in the original string. When several letters tie for most frequent, take the one that comes first in the alphabet.

Shifting by a letter means advancing a letter by that letter's position in the alphabet, wrapping from z back to a. The letter a is position 1 and z is position 26, so a shift by c turns b into e and z into c.

Counts always come from the original letters, never from letters the encryption has already produced. If the string is $k$ letters long or shorter, write it out unchanged.

The first line contains $k$ ($1 \le k \le 10000$).

The second line contains the string, made of $c$ lowercase letters ($1 \le c \le 100000$).

Print the encrypted string on one line.