''' Purpose: find the word of the longest length amongst the input
'''

# get the words
reply = input( "Enter a series of words: " )
words = reply.split()

# need to keep track of the longest word seen so far. It's initialization
# should never prevent a word of longest length being missed

...

# consider the words one by one

for word in words :

    # check the word out - compare its length to longest so far
    # if current word is longer than the longest word so far, need to update

    ...

# longest word so far must be longest as considered every word as a possibility

# print longest word
...