#include<stdio.h>
int main()
{
	char x[50];
	int n;
	scanf("%d", &n);
	getchar();
	gets(x);
	for (int i = 0; x[i] != '\0'; i++)
	{
		if (x[i] + n > 'z')
		{
			printf("%c", x[i] + 'n' - 'z' + 'a'-'1');
		}
		else
		printf("%c", x[i] + n);
	}
	return 0;
}