#!/usr/bin/python3
import sys

words = [ ]
for filename in sys.argv[1:]:
	for line in open(filename):
		line = line.strip().lower()
		try:
			words[len(line)][line] = None
		except IndexError:
			while len(words) <= len(line):
				words.append({})
for i in range(len(words)):
	words[i] = sorted(words[i].keys())

print('words =', words)