defmodule Main do
  def main do
    input_solve()
    |> IO.puts()
  end

  def input_solve() do
    input_solve_rec([0, 0, 0])
    |> (fn [a, b, c] -> [a, b, c |> div(2)] end).()
    |> Enum.min()
  end

  def input_solve_rec(result) do
    case IO.read(1000) do
      :eof -> result
      s -> input_solve_rec(count_tre(s |> String.to_charlist(), result))
    end
  end

  defp count_tre([], [t, r, e]) do
    [t, r, e]
  end

  defp count_tre(s, [t, r, e]) do
    tl(s)
    |> count_tre(
      cond do
        hd(s) == ?t -> [t + 1, r, e]
        hd(s) == ?r -> [t, r + 1, e]
        hd(s) == ?e -> [t, r, e + 1]
        true -> [t, r, e]
      end
    )
  end
end