#include <bits/stdc++.h>

using namespace std;

int main() {
    ios::sync_with_stdio(false); //读入输出优化的强迫症
    int n;
    string s;
    cin >> n;
    cin >> s;
    //遍历字符串的第一位char
    for (int i = 0; i < s.length(); i++) {
        int c = s[i] + n;
        while (c > 122) {
            c = c - 122 + 97-1;
        }
        s[i] = char(c);
    }
    cout << s << endl;
    return 0;
}