#include<iostream>
using namespace std;
int main(){
    string s;
    int n,i,j;
    cin>>n;
    cin>>s;
    for(i=0;i<s.size();++i)
    {
        for(j=1;j<=n;++j)
        {
            ++s[i];
            if(s[i]>'z')
            s[i]='a';
        }
    }
    cout<<s;
	return 0;
}```