lllllllll

#include<bits/stdc++.h>
using namespace std;
int main(){
int a;
string s;
cin >>a>> s;
for(int i=0;i<=s.size();i++){
s[i] = char(s[i] - 'a' + a) % 26 + 'a';
}
cout<<s;
return 0;
}