#include<stdio.h>
#include<string.h>
#include<math.h>

char a[105];
int main()
{
	int n;
	scanf("%d", &n);
	scanf("%s", a);
	for (unsigned int i = 0; i < strlen(a); i++)
	{
		a[i] = a[i] + n;
		while (a[i] > 'z')
			a[i] = a[i] - 26;
		printf("%c", a[i]);
	}
	return 0;
}