int main()
{
    BigNumber n = "12345678";
    printf("%s\n", n.ToStr().c_str());

    n = 987654321;
    printf("%s\n", n.ToStr().c_str());

    n = "98765432109876543210";
    printf("%s\n", n.ToStr().c_str());

    std::cout << n << std::endl;

    n = "25";
    n *= 25;
    std::cout << n << std::endl;

    std::cout << n - "25" << std::endl;

    return 0;
}