are there any bugs?
int main() {
    char phone[11];
    int i;

    scanf("%s", phone);
    scanf("%d", &i);

    if (i < -1 || i > 9) {
        printf("ERROR");
        return 1;
    } else if (i == -1) {
        printf("%s", phone);
    } else {
        printf("%c", phone[i]);
    }

    return 0;
}