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


int main ()
{
    int n;
    cin>>n;
    char ch;
    cin.get();
    while((ch=getchar())!='\n'){
        if(ch+n > 'z'){
            ch = 'a'+(n-1-('z'-ch))%26;
        }
        else
            ch += n;
        cout<<ch;
    }
   return 0;    
}