#include<iostream>
#include<cstring>
using namespace std;
int main()
{
	char s[50];
	int n;
	cin >> n;
	n = n % 26;
	cin >> s;
	for (int i = 0; i < strlen(s); i++)
	{
		while (s[i] + n > 'z')
		{
			s[i] = s[i] + n - 26;
		}
		s[i] = s[i] + n;
	}	
	cout << s;
	return 0;
}