#!/usr/bin/env python
#-*-coding:utf8-*-
import sys
import itertools
import codecs
import re
def is_palindrome(string_to_check):
    reverse_string = string_to_check[::-1]
    return string_to_check ==  reverse_string
def load_words(words_file='file.txt'):
    with codecs.open(words_file, encoding='utf-8') as wf:
        list_words = wf.read()
    list_words = ''.join(re.sub('[/.!,;+()#&?=<>|%$-]', '', list_words))
    return list_words.lower().split()
def combinator_words(list_words):
    for current_stage in range(len(list_words),1,-1):
        iter = itertools.combinations(list_words,(current_stage))
        while True:
            try:
                current_mutation = iter.next()
            except StopIteration:
               break
            string = ''.join(current_mutation)
            if is_palindrome(string): return ' '.join(current_mutation)
if __name__ == '__main__':
    list_words = load_words(sys.argv[1]) # имя файла с исходным текстом
    print (combinator_words(list_words))

s1==s2[::-1][0:len(s1)]

s1[::-1]==s2[0:len(s1)]