#include <stdio.h>
#include <string.h>
int main()
{
	char sb[999] = { 0 };
	int n, len;

	scanf("%d", &n);
	scanf("%s",sb);
	len = strlen(sb);
	for (int i = 0; i < len; i++)
	{
		sb[i] += n;
	}
	for(int i = 0; i < len; i++)
	{
		if (sb[i] > 122)
		{
			sb[i] -= 26;
		}
		printf("%c", sb[i]);
	}
	return 0;
}