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