# frozen_string_literal: true

class Array
  def points
    (0..size).map do |n_left|
      left = take(n_left)
      right = drop(n_left)

      left.sum - right.sum
    end
  end
end

def solve
  diffs = A.each_slice(2).map { |l, r| l - r }
  diffs.points.max
end

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

puts solve