#include <bits/stdc++.h>
using namespace std;
string a;
int n, b, c;
void shu_ru() {
	cin >> n >> a;
}

void ji_suan() {
	b = a.size();
	n = n % 26;
	for (int i = 0; i < b; ++i) {
		if (n > (int)a[i]) {
			c = (int)a[i];
		}
	}
	n -= c;
	for (int i = 0; i < b; ++i) {
		a[i] += n;
	}
}

void shu_chu() {
	cout << a;
}

int main() {
	shu_ru();
	ji_suan();
	shu_chu();
}