PYTHON 2.7.13
Each function must be aswered RECURSIVELY, NO LOOPS ALLOWED
Write a function called acronym. This function is passed a string s, and returns a string consisting of all of the capitalized letters in s. For example:
def acronym(s):
>>> acronym('United States of America')
'USA'
>>> acronym('Depaul University')
'DPU'
>>> acronym('the University of Illinois at Chicago')
'UIC'