set={}
File.open(ARGV.shift) do |fp|
  for line in fp
    line.chomp!
    set[line[0,4]]=line
  end
end
File.open(ARGV.shift) do |fp|
  for line in fp
    cccc=line.chomp[0,4]
    set.delete(cccc)
  end
end
for line in set.values
  puts line
end