public void setPastDays(long days) {
        pastDays = days;

        year = (int)(days / 365);
        long tmpDays = year * 365 + (year / 4) - (year / 100) + (year / 400);

        while (days <= tmpDays) {
            year--;
            tmpDays = year * 365 + (year / 4) - (year / 100) + (year / 400);
        }

        days -= tmpDays;
        year++;

        for (month = 0; days > 0; days -= monthDays[month++]) {
            if (month == 1 && isLeapYear(year)) {
                days--;
            }
        }

        date = (int)days + monthDays[month - 1];
        if (month == 2 && isLeapYear(year)) {
            date++;
        }
    }