#include <stdbool.h>
#include <math.h>
#include <ctype.h>
int main() {
	int n,i = 0;
	char b[50],c[50];
	scanf("%d",&n);
	scanf("%s",&b);
	while(b[i] != '\0'){
		if(b[i] + n>='a'&&b[i] + n<='z'){
			c[i] = (b[i] + n);
		}
		else{
			c[i] = b[i] + 26 -n;
		}
		i++;
	}
	printf("%s",c);
	return 0;
}