int 
uc_day_of_week(int day, int month, int year)
{
	int cent;

	/* adjust months so February is the last one */
	month -= 2;
	if (month < 1) {
		month += 12;
		--year;
	}
	/* split by century */
	cent = year / 100;
	year %= 100;
	return ((26 * month - 2) / 10 + day + year
			   + year / 4 + cent / 4 + 5 * cent) % 7;
}