#include<bits/stdc++.h>
using namespace std;

int main() {
    int n;
    string s;
    cin >> n >> s;
    n %= 26;
    for(int i = 0; i < s.size(); ++i) {
        s[i] += n;
        if(s[i] > 'z') s[i] = s[i] - 'z' - 1 + 'a';
        else if(s[i] < 'a') s[i] = 'z' - ('a' - s[i]) + 1;
    }
    cout << s;
    return 0;
}