void sort_students(struct Student arr[], int n) {
    struct Student temp;
    for (int i = 0; i < n-1; i++) {
        for (int j = i+1; j < n; j++) {
            if (arr[i].score < arr[j].score ||
                (arr[i].score == arr[j].score && strcmp(arr[i].first_name, arr[j].first_name) > 0) ||
                (arr[i].score == arr[j].score && strcmp(arr[i].first_name, arr[j].first_name) == 0 && strcmp(arr[i].last_name, arr[j].last_name) > 0)) {
                temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
    }
}