# -*- coding: utf-8 -*-
"""

  Codifica y decodifica en codigicación Caesar.

"""

import operator

__pychecker__='no-stringiter'
# pylint: disable=W0402

import string 

def main ():

    """
    Programa principal.
    """
    
    try:
        letters = string.ascii_letters + \
                  string.punctuation + \
                  string.digits
        shift   = 3
        
        choice  = raw_input("Want to encode or decode?: ")
        options = { 'encode' : operator.add,
                    'decode' : operator.sub }
        oper = options [choice]
        
        word = (raw_input("Enter the text: "))
        
        encoded = ''.join (
            x if x.isspace () else
            letters [oper (letters.index(x), shift) %
                     len (letters)]
            for x in word)
        print encoded

    except KeyError:
        print "Wrong option"
    except ValueError:
        print "Wrong input"

if __name__ == '__main__':
    main ()