m = []
s = []
while 1:
  x = input().strip().split()
  if x[0] == 'end':
    break
  if x[0] not in m:
    m.append(x[0])
    s.append([x[0]])
    for i in range(1,len(x)):
      if x[i] not in s[-1]:
        s[-1].append(x[i])
  else:
    f = m.index(x[0])
    for i in range(1,len(x)):
      if x[i] not in s[f]:
        s[f].append(x[i])
s.sort(key = lambda k: len(k))
u = []
for i in s:
  for j in range(1,len(i)):
    if i[j] not in u:
      u.append(i[j])
      print(i[0],i[j])
      break

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QXBwbGUgQSBCIEMgRApCYW5hbmEgRSBGIEcgRyBHIEcKQ2F0IEggSiBLCkRvZyBBIEggRSBGIEcgRCBCCmVuZA==

Apple A B C D
Banana E F G G G G
Cat H J K
Dog A H E F G D B
end