import random
import sys
MAXGEN = 10000
NONWORD = '
'
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