#include<iostream>
#include<string>
using namespace std;

int main()
{
	int n;
	string a;
	cin >> n;
	cin >> a;
	int i;
	for (i = 0; i < a.size(); i++)
	{
		a[i] = a[i] + n;
		if (a[i] > 'z')
			a[i] = a[i] - 26;
	}
	cout << a;
	return 0;
}