class Teste {

    public static int seuComparador(String a, String b) {
        String c = a;
        String d = b;
        while (c.length() < d.length()) c = "0" + c;
        while (c.length() > d.length()) d = "0" + d;
        return c.compareTo(d);
    }

    public static void main(String[] args) {
        System.out.println(seuComparador("0", "3"));
        System.out.println(seuComparador("10", "3"));
        System.out.println(seuComparador("007", "300"));
        System.out.println(seuComparador("40", "040"));
    }
}