How can I get 2 characters from the middle of a string?

Question

import time

date = time.strftime("%d:%m:%y")


print date #returns '18:05:14'

print date[-2:] #returns '14'

print date[:2] #returns '18'

#print ??? <-returns '05'

How can I (preferably) use the [:number:] thing to look for the 4th and 5th character ONLY of "18:05:14" (05)? if i can't use [:#], that's fine. I can't find any possible way, but any help is appreciated.