def odai_11_911(h, words)
  w = (words.map do |e|
         h[e]
       end).compact
 
  if w == []
    # 新規
    vmax = h.values.compact.uniq
    vnext = vmax == [] ? 0 : vmax.max + 1
    words.map do |e|
      h[e] = vnext
    end
  else
    # 既存
    vmin = w.min
    vmax = w.max
    words.map do |e|
      h[e] = w.min
    end
    h.map do |k, v|
      h[k] = vmin if v == vmax
    end
  end
  h
end
 
h = {}
while w = gets
  w = w.chomp
  words = w.split(' ')
  h = odai_11_911(h, words)
end
 
h.values.uniq.map do |n|
  p (h.map do |k, v|
       v == n ? k : nil
     end).compact
end# your code goes here

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