# frozen_string_literal: true

N = gets.to_i
AS = gets.chomp.split.map(&:to_i)

remain = AS

diff = 0
loop do
  left = remain[0] - remain[1]
  right = remain[-1] - remain[-2]
  if left < right
    remain.pop
    remain.pop
    diff += right
  else
    remain.shift
    remain.shift
    diff += left
  end
  break if remain.empty?
end

puts diff