#include<stdio.h>



int main()
{
	int n,x;
	char c;
	scanf("%d", &n);
	getchar();
	while ((c = getchar()) != '\n')
	{
		x = (c + n) % 122;
		if (x > 97 && x < 122)c += n;
		else
		{
			c = 'a' + x - 1;
			if (x == 0)c = 'z';
		}
		printf("%c", c);
	}
	return 0;
}