#include<bits/stdc++.h> 

using namespace std;
int n;
char s[60];
int main(){
    cin >> n;
    scanf("%s",s + 1);
    int len = strlen(s + 1);
    for(int i = 1;i <= len;i++){
    	s[i] = s[i] + n;
    	if(s[i] >= 122){
            int t = s[i] - 122;
	    s[i] = 97 + t;
	}
	cout << s[i];
	}
	return 0;
}