#include<stdio.h>
#include<string.h>
int main()
{
	int n;
	scanf("%d",&n);
	char ch[51];
	scanf("%s",ch);
	n=n%26;
	for(int j=0;j<strlen(ch);j++){
	
			ch[j] = ch[j]+n+1<=('a'+26) ? ch[j]+n : n-'z'-ch[j];
					
	}
		puts(ch);
	
	return 0;
}