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

int main() {
    int n;
    char ch;

    scanf("%d", &n);

    char name[1001];
    scanf("%s", name);

    int bianjie = strlen(name);
    for (int i = 0; i < bianjie; i++){
        name[i] = ((name[i] - 'a' + n) % 26) + 'a';
    }

    printf("%s", name);

    return 0;
}