# frozen_string_literal: true

class Array
  def center
    Rational(max + min, 2).then do |i|
      [i.floor - 1,
       i.floor,
       i.ceil,
       i.ceil + 1]
    end
  end
end

def solve
  Y.center.map { |i| Y.map { |y| (y - i).abs }.sum }.min
end

N = gets.to_i
Y = gets.split.map(&:to_i)

puts solve