An integer k is entered (1 <= k <= 365). Determine which day of the week (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday or Sunday) is the k-th day of a non-leap year in which January 1 is Monday.

def day_of_week(k):
    if k < 1 or k > 365:
        return None
    days_in_year = 365
    days_elapsed = k % days_in_year
    day = (days_elapsed + 1) % 7
    day_of_week = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
    return day_of_week[day]

day_of_week(10)