n = int(input())
a = list(map(int, input().split()))
if n == 0:
    print(0)
    exit()

global_max = max(a)
global_min = min(a)

sum_ans = 0
abs_global_max = abs(global_max)
abs_global_min = abs(global_min)

for num in a:
    if num == global_min:
        current = max(abs_global_max, abs_global_min)
    else:
        current = max(abs_global_max, abs(num))
    sum_ans += current

print(sum_ans)