#include<stdio.h>
#include<string.h>
int main(void)
{	int n,i;
	char a[100],ch;
	scanf("%d",&n);
	ch = getchar();   //吃回车 
	gets(a);
	for(i=0;i<strlen(a);i++){
		if(a[i]+n<='z')a[i] = a[i] + n;
		else a[i] = 'a' - 1 + n - ('z' - a[i]);
	}
	for(i=0;i<strlen(a);i++)
		printf("%c",a[i]);
}