#!/usr/bin/env python
"""
Learn a new alphabet by deciphering a
list of words in an efficient way.
"""
import re, sys
sys.path.append('/home/user/.pylib/')
from utils import freq
import codecs
from unicodedata import category
sys.stdin = codecs.getreader('utf-8')(sys.stdin)
sys.stdout = codecs.getwriter('utf-8')(sys.stdout)

def regexify(letters):
	letters = u''.join([letter for letter in letters if category(letter)[0] not in (u'PZC')])
	return re.compile('^[%s]+$' % letters)

words = [word.split('\t')[1] for word in sys.stdin]
text = ''.join(words)
letterfq = dict(freq(list(text)))
common = sorted(list(set(letterfq)), key=lambda letter: letterfq[letter], reverse=True)

def find_matches(letters):
	return filter(lambda w: re.match(regexify(letters), w), words)

for i in range(len(common)):
	print u' '.join(common[:i])
	pattern = ''.join(common[:i])
	if len(pattern)>0: 
		for match in find_matches(pattern):
			print "\t" + match