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

minus = 0
absmin = 10**9
sum = 0

for i in 0..N-1 do
  if a[i] < 0
    minus += 1
    a[i] = -a[i]
  end
  tmp = a[i].abs
  sum += tmp
  absmin = tmp if absmin > tmp
end

if minus %2 == 0
  puts sum
else
  puts sum - 2*absmin
end
