#include <iostream>
#include <string>
using namespace std;
int main() {
    int n;
    string s;
    cin >> n;
    cin >> s;
    for (int i = 0; i < s.length(); i++) {
        s[i] = (s[i] - 'a' + n) % 26 + 'a';
    }
    cout << s << endl;
    return 0;
}