defmodule Main do
  def main do
    1..(IO.read(:line)
        |> String.trim()
        |> String.to_integer())
    |> Enum.map(fn _ ->
      IO.read(:line)
      |> String.trim()
      |> String.split()
    end)
    |> solve_rec([])
    |> IO.puts()
  end

  def solve_rec([], r) do
    r
  end

  def solve_rec([[t, s] | l], r) do
    case t do
      "0" -> solve_rec(l, "#{r}#{s}")
      "1" -> solve_rec(l, "#{s}#{r}")
    end
  end
end