weekdays = ["man", "tir", "ons", "tor", "fre", "lør", "søn"]

def ily(year): # ily = is_leap_year()
    return True if year % 400 == 0 else False if year % 100 == 0 else True if year % 4 == 0 else False

def weekday_newyear(year):
    if year == 1900:
        return 0

    else:
        if ily(year):
            return ((year - 1900) + (year - 1900) // 4 - 1) % 7

        else:
            return ((year - 1900) + (year - 1900) // 4) % 7

def is_workday(weekday):
    return False if weekday in (5, 6) else True

def workday_in_year(year):
    weekday = weekday_newyear(year)

    if not ily(year):
        return 261 if is_workday(weekday) else 260

    else:
        return 262 if weekday in range(4) else 261 if weekday == 4 else 260