#include <string>

class Date {
 public:
  Date(int year, int month, int day): year_(year), month_(month), day_(day) {}
  bool IsLeap() const {
    return ((this->year_ % 4) == 0 && (this->year_ % 100 != 0)) ||
        (this->year_ % 1000 == 0) ||
        (this->year_ % 400 == 0);
  }
  std::string ToString() const {
    std::string d = std::to_string(this->day_);
    d = d.length() == 1 ? "0" + d : d;
    std::string m = std::to_string(this->month_);
    m = m.length() == 1 ? "0" + m : m;
    std::string y = std::to_string(this->year_);
    for (int i = y.length(); i < 4; ++i) {
      y = "0" + y;
    }
    return d + "." + m + "." + y;
  }
  Date DaysLater(int days) const {
    Date result(this->year_, this->month_, this->day_ + days);
    while (true) {
      int i_days = this->GetMonthDays(result);
      if (result.day_ <= i_days) {
        break;
      }
        result.day_ -= i_days;
        ++result.month_;
      if (result.month_ > 12) {
        result.month_ = 1;
        ++result.year_;
      }
    }
    return result;
  }
  int DaysLeft(const Date& date) const {
    return JDN(date.year_, date.month_, date.day_) -
    JDN(this->year_, this->month_, this->day_);
  }

 private:
  int JDN(const int& year, const int& month, const int& day) const {
    int a = (14 - month) / 12;
    int y = year + 4800 - a;
    int m = month + 12 * a - 3;
    return day + ((153 * m + 2) / 5) +
    (365 * y) + (y / 4) - (y / 100) + (y / 400) - 32045;
  }
  int GetMonthDays(const Date& date) const {
    static const int days_in_month[12] = {31, 28 , 31, 30, 31, 30,
                                      31, 31, 30, 31, 30, 31};
    if (date.month_ == 2 && date.IsLeap()) {
      return 29;
    }
    return days_in_month[date.month_ - 1];
  }
  int year_, month_, day_;
};