public static String intToString(int n) {
        if (n == 0) return "Zero";
        if (n < 0) return "Negative " + intToString(-n);
        String ret = "";
        int i = 0;
        while (n > 0) {
            String hundredSegment = convertHundred(n % 1000);
            if (!hundredSegment.isEmpty()) {
                ret = hundredSegment + bigs[i] + " " + ret;
            }
            n /= 1000;
            ++i;
        }
        return ret.trim();
    }