#include<stdio.h>
int main()
{
	int i,n;
	char c[52],c1,c2[50]={0},cn;
	for (i = 0; i < 26; i++)
	{
		c[i] = 'a' + i;
	}
	for (i = 26; i < 52; i++)
	{
		c[i] = 'a' + i - 26;
	}
	scanf("%d", &n);
	n = n % 26;
	scanf("%c", &cn);
	for (i=0;;i++)
	{
		scanf("%c", &c1); 
		if (c1 >= 'a'&&c1<='z')
		{
			c2[i] = c[c1 - 'a' + n];
		}
		else
			break;
	}
	puts(c2);
	return 0;
}