defmodule Main do
  def main do
    [_, k] =
      IO.read(:line)
      |> String.trim()
      |> String.split()
      |> Enum.map(&String.to_integer/1)

    IO.read(:line)
    |> String.trim()
    |> solve(k)
    |> IO.puts()
  end

  def solve(s, k) do
    {a, b} = s |> String.split_at(k - 1)
    b <> a
  end
end