#include<iostream>
#include<algorithm>
#include<cstring>

using namespace std;

int n;
char a[200];
int len;

int main() {
	cin >> n >> a;
	len = sizeof(a);
	for (int i = 0; i < len; i++) {
		a[i] = char(a[i] + n);
		if (a[i] > 'z') a[i] = char(a[i] % 122 + 96);
	}
	cout << a;
    return 0;
}