# Asks for a stating day of the week
# Returns that day as a str
def get_day_leaving():
    print('Enter a day of the week you plan to leave... i.e. "Monday"')
    userInput  = input('Please enter a day of the week: ')
    day = userInput.lower()
    return day

# Takes the starting day from the user and finds it in "week"
# Returns the index value of position in "week"
def get_day_index(week, starting_day_result):
    dayIndex = week.index(starting_day_result)
    return dayIndex

# Asks for how many days to be gone
# Returns the int
def get_days_gone():
    userInput = input('How many days will you be gone?: ')
    daysGone = int(userInput)
    return daysGone

# Adds the starting day index value from "week" with the amount of days to be gone
# Return the total
def add_days(index_result, days_gone_result):
    startToEnd = index_result + days_gone_result
    return startToEnd

# Input the total days gone
# Return the day of the week returning
def day_coming_back(week, days_gone):
    dayBack = days_gone % len(week)
    weekday_back = week[dayBack].capitalize()
    return weekday_back

# Main Program
def main_program():
    #Days of the week
    week = ['sunday', 'monday', 'tuesday', 'wednesday',
            'thursday', 'friday', 'saturday']

    leaving_day = get_day_leaving() # starting day
    leaving_day_index = get_day_index(week, leaving_day) # index value
    days_gone = get_days_gone() # days gone
    start_to_end = add_days(leaving_day_index, days_gone) # total of index and days gone
    day_back = day_coming_back(week, start_to_end)
    print('You will be back on a ' + day_back)

main_program()