# frozen_string_literal: true

class Array
  def average
    Rational(sum, size).to_f
  end
end

def solve
  Y.average.then { |a| [a.floor, a.ceil] }.map { |i| Y.map { |y| (y - i).abs }.sum }.min
end

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

puts solve