N = gets.to_i
R = N.times.map { gets.split.map(&:to_i) }

ans = []
queue = []

R.each do |cnt, *a|
  next if cnt == 0
  queue << a
end

until queue.empty?
  list = queue.shift
  id = list.shift
  ans << id
  next if list.empty?

  queue << list
end

puts ans.join(' ')