def qs(er)
h = Hash.new Float::INFINITY
erc = 0
er.each do |r|
min = r.map{|e| h[e]}.min
ern = min == Float::INFINITY ? erc += 1 : min
r.each{|e| h[e] = ern}
end
h.group_by(&:last).values.map{|s| s.map(&:first).sort}
end
er = $<.readlines.map &:split
puts qs(er).map{|a| a * ' '} * $/
ZGVmIHFzKGVyKQogIGggPSBIYXNoLm5ldyBGbG9hdDo6SU5GSU5JVFkKICBlcmMgPSAwCiAgZXIuZWFjaCBkbyB8cnwKICAgIG1pbiA9IHIubWFwe3xlfCBoW2VdfS5taW4KICAgIGVybiA9IG1pbiA9PSBGbG9hdDo6SU5GSU5JVFkgPyBlcmMgKz0gMSA6IG1pbgogICAgci5lYWNoe3xlfCBoW2VdID0gZXJufQogIGVuZAogIGguZ3JvdXBfYnkoJjpsYXN0KS52YWx1ZXMubWFwe3xzfCBzLm1hcCgmOmZpcnN0KS5zb3J0fQplbmQKCmVyID0gJDwucmVhZGxpbmVzLm1hcCAmOnNwbGl0CnB1dHMgcXMoZXIpLm1hcHt8YXwgYSAqICcgJ30gKiAkLw==
Z29vc2UgcGlnZW9uCmNhdCBkb2cKZWVsIGdvbGRmaXNoCmdvb3NlIGR1Y2sKaG9yc2UgZG9nCmNvZCBlZWwKZG92ZSBwaWdlb24KZG9nIHJoaW5vCmdvbGRmaXNoIHNxdWlkCmdvb3NlIGxhcmsKc3F1aWQgbGFyaw==
goose pigeon
cat dog
eel goldfish
goose duck
horse dog
cod eel
dove pigeon
dog rhino
goldfish squid
goose lark
squid lark