class Yukicoder
  def initialize
    n = gets.chomp.to_i
    a = gets.chomp.split(' ').map(&:to_i)
    min_move_count = Float::INFINITY

    1.upto(100) do |num|
      array = pyramid_array(num)
      move_count = 0
      from_count = 0
      to_count = 0

      break if a.inject(:+) < array.inject(:+)

      a.each_with_index do |num, index|
        count = num - (array[index] || 0)
        if count < 0
          from_count += count
        else
          to_count += count
        end
      end

      move_count = [from_count, to_count].min + [from_count, to_count].max - [from_count, to_count].min

      min_move_count = [min_move_count, move_count].min
    end

    puts min_move_count
  end

  def pyramid_array(num)
    [1] if num == 1

    [*(1..num-1)] + [num] + [*(1..num-1)].reverse
  end
end

Yukicoder.new