#!/usr/bin/python
import sys, os, re
pattern = re.compile('\w+')

def words():
 words = []
 if len(sys.argv) > 1:
  for arg in sys.argv[1:]:
   input = open(arg)
   words += getwords(input)
   input.close()
 else:
  words += getwords(sys.stdin)
 words = unique(words)
 for word in words:
  print word

def getwords(input):
 lines = input.readlines()
 data = ' '.join(lines)
 return pattern.findall(data)

def unique(words):
 wordlist = {}
 for word in words:
  if wordlist.has_key(word):
   wordlist[word] += 1
  else:
   wordlist[word] = 1
 words = wordlist.keys()
 words.sort(lambda a, b: cmp(wordlist[b], wordlist[a]))
 return words  # sorted by frequency

if __name__ == '__main__':
 words()
else:
 pass