问题4172--B

4172: B

[命题人 : ]
时间限制 : 1.000 sec  内存限制 : 128 MB

题目描述

You have a sequence of lowercase characters that you want to encrypt. The first k characters will be encoded as plain-text. All characters after the first k characters will be shifted by the most frequently occuring character that appeared in the previous k characters, with ties broken by the character which occurs first in the alphabet. By "shifted by", we mean that if c was the most frequently occuring character, the character would be shifted ahead by 3 positions (since c is the third letter of the alphabet), modulo 26 (e.g., b becomes e, and z becomes c).

输入

On the first line of input contains k (1 ≤ k ≤ 10 000). The next line contains c characters (1 ≤ c ≤ 100 000).

输出

One line, containing the encrypted version of the c characters from the input.

样例输入 Copy

5
abbaabbacdecde

样例输出 Copy

abbaacdcdegdgh

提示

来源/分类