#include <iostream>
//#include <bits/stdc++.h>
using namespace std;
int main() {

    int x;
    cin >> x;
    string s;
    cin >> s;

    string alphabet = "abcdefghijklmnopqrstuvwxyzyxwvutsrqponmlkjihgfedcba";
    for(int i = 0; i < s.length(); i++) {
        int mesto = s[i] - 'a';
        mesto += x;

        cout << alphabet[mesto];
    }
    return 0;
}