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

minus_cnt = 0
abs_min = Float::INFINITY
sum = 0
N.times{|x|
    if (As[x] < 0) then
        minus_cnt += 1
    end
    sum += As[x].abs
    abs_min = [abs_min, As[x].abs].min
}
ans = 0
if (minus_cnt % 2 === 0) then
    ans = sum
else
    ans = sum - (2 * abs_min)
end

puts ans
