#include<iostream>
#include<cstring>
using namespace std;
char a[51];
int main() {
	int n;
	cin >> n >> a;
	int b = strlen(a);
	for (int i = 0;i<b; i++) {
		a[i] += n;
		if (a[i] > 122)
			a[i] = a[i] % 122 + 96;
	}
	cout << a;
}