 #!/usr/bin/python

'''
URLify:
Write a method to replace all spaces in a input_string with '%20'.
You may assume that the input_string has sufficient space at the end of the input_string
to hold the additional characters, and that you are given the "true" length of the input_string
EXAMPLE
Input: "Mr John Smith   ", 13
Output: "Mr%20John%20Smith"
'''