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
    _n = ii()
    bs = li()

    {_, ans} = for b <- bs, reduce: {0, 0} do
      {excess, ans} ->
        {excess + b - 1, ans + abs(excess)}
    end
    IO.puts ans
  end
end