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

int main() {
    int t;
    int n;
    char *ptr = NULL;
    char *s = NULL;
    scanf("%d", &t);

    for (int i = 0; i < t; i++) {
        scanf("%d", &n);
        ptr = malloc(n + 1);
        s = malloc(n + 1);
        scanf("%s", ptr);
        int len = strlen(ptr);
        for (int index = len - 1; index >= 0; index--) {
            s[len - index - 1] = ptr[index];
        }
        printf("%s\n", s);
        memset(ptr, 0, n + 1);
        memset(s, 0, n + 1);
        free(ptr);
        free(s);
        ptr = NULL;
        s = NULL;
    }

}