import string

 

# word = "fabricate"

# print ''.join([chr(ord(letter)-3) for letter in word])

# string.ascii_lowercase - 'abcdefghijklmnopqrstuvwxyz'

 

letters = string.ascii_lowercase

offset = 3

 

while True:

    word = raw_input("Enter word").lower()

    reenter = False

    for s in word:

        if s not in letters:

            print "INVALID. Entry must be all alpha characters!"

            reenter = True

            break

    if not reenter:

        break

       

print "Entered word: %s" % word

print "Offset word: %s" % ''.join([letters[letters.index(letter)-offset] for letter in word])