defmodule Main do
  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)
  def yn(b), do: IO.puts(if b, do: "Yes", else: "No")

  def main do
    s = input() |> String.to_charlist
    f(s, 0, -1)
    |> IO.puts
  end

  def f(xs, k, m) do
    case xs do
      [?p, ?a, ?i, ?n | ys] -> f(ys, 0, max(k-1, m))
      [?p, ?o, ?n | ys] -> f(ys, k+1, m)
      [_ | ys] -> f(ys, k, m)
      [] -> m
    end
  end
end