import random
import sys
MAXGEN = 10000
NONWORD = '\n'
w1 = w2 = NONWORD
statetab = {}
text = sys.stdin.read()
words = text.split()
for word in words:
  statetab.setdefault((w1, w2),[]).append(word)
  w1, w2 = w2, word
# add tail
statetab.setdefault((w1, w2),[]).append(NONWORD)
# show mar words
w1 = w2 = NONWORD
for i in xrange(MAXGEN):
  suf = statetab[(w1,w2)]
  t = random.choice(suf)
  if t == NONWORD:
 break
  print t
  w1, w2 = w2, t