defmodule Main do
  def main do
    n = ii()
    xs = for _ <- 1..n, into: [] do
      [a, b] = input() |> String.split
      {a, b}
    end

    for {a, b} <- Enum.sort(xs, &cmp/2) do
      IO.puts "#{a} #{b}"
    end
  end

  def cmp({a, b}, {c, d}) do
    if a == c do
      b <= d
    else
      a <= c
    end
  end

  def input, do: IO.read(:line) |> String.trim
  def ii, do: input() |> String.to_integer
  def li, do: input() |> String.split |> Enum.map(&String.to_integer/1)
end