n = gets.to_i
as = gets.split(' ').map(&:to_i)
abs_min = 1000000000
count = 0
sum = 0
as.each do |a|
    if a <= 0
        count += 1
    end
    sum += a.abs
    abs_min = a.abs if a.abs <= abs_min
end
if  count%2 == 0
    ans = sum
elsif count%2 == 1
    ans = sum - abs_min*2
end
puts ans
