Programme will not returns the day number not the day name

[Oldman45]

I have the following programme:

n = input("Enter a number 0 to 6: ")
day_of_the_week = n

def day_of_the_week ():
    if n == 0:
        return "Sunday"
    elif n == 1:
        return "Monday"
    elif n == 2:
        return "Tuesday"
    elif n == 3:
        return "Wednesday"
    elif n ==4:
        return "Thursday"
    elif n == 5:
        return "Friday"
    elif n == 6:
        return "Saturday"
    else:
        return "Invalid number"

print("The day of the week is ", n)

The out put I get is:

Output:
Python 3.8.4 (tags/v3.8.4:dfa645a, Jul 13 2020, 16:46:45) [MSC v.1924 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license()" for more information.
>>> 
= RESTART: C:/Users/John/Documents/John''s files/Work/Coding/Think Like a Computer Scientist/Programmes/day_of_the_week.py
Enter a number 0 to 6: 4
The day of the week is  4
>>> 

Could anyone please advise what I am doing wrong?