def julianDay(year, month, day):
    """Convert a date to Julian

    :param int `year`: the year
    :param int `month`: the month
    :param int `day`: the day

    :returns: the julian date number

    """
    b = 0
    if month > 12:
        year = year + month // 12
        month = month % 12
    elif month < 1:
        month = -month
        year = year - month // 12 - 1
        month = 12 - month % 12
    if year > 0:
        yearCorr = 0
    else:
        yearCorr = 3
    if month < 3:
        year = year - 1
        month = month + 12
    if year * 10000 + month * 100 + day > 15821014:
        b = 2 - year // 100 + year // 400
    return (1461 * year - yearCorr) // 4 + 306001 * (month + 1
        ) // 10000 + day + 1720994 + b
