Write a Python program that will ask a customer how many fluid ounces they would like to drink. The program will then print out the size of cup that they need based upon the following criteria:

1) A drink with 12 or fewer ounces is considered to be "small".

2) A drink with more than 12 but 20 or fewer ounces is considered to be "medium".

3) A drink with more than 20 but 32 or fewer ounces is considered to be "large"

4) A drink with more than 32 ounces is considered to be "extra large".