def days_per_month(month, year):
    """Return the number of days in any month and year"""
    days = [30, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
    d = days[int(month)-1]
    if d==28 and int(year)%4==0:
        if int(year)%100==0 and int(year)%400!=0:
            pass
        else:
            d = 29
    return d