string factors56(int n) {
    ostringstream stream;

    if ((n % 5 == 0) && (n % 6 == 0)) {
        stream << n << " is divisible by both 5 and 6";
        return stream.str();
    }
    else if ((n % 5 == 0 || n % 6 == 0) && !((n % 5 == 0) && (n % 6 == 0))) {
        stream << n << " is divisible by 5 or 6, but not both";
        return stream.str();
    }
    else {
        stream << n << " is not divisible by either 5 or 6";
        return stream.str();
    }
}