#include <stdio.h>

int main()
{
	
	int i,c;
	char b[50] = {0};
	scanf("%d", &c);
	scanf("%s", b);
	for (i = 0; b[i] != '\0'; i++)
	{
		b[i] = b[i] +c;
		while (b[i] > 'z')
			b[i] = b[i] - 26;
	}
	printf("%s", b);
}