AOJ-0017 Caesar Cipher

0017.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import sys, string

alphabet = 'abcdefghijklmnopqrstuvwxyza'
table = string.maketrans(alphabet[:-1], alphabet[1:])
for s in sys.stdin:
    while not('the' in s or 'this' in s or 'that' in s):
        s = s.translate(table)

    print s[:-1]