n = int(input())
a = list(map(int, input().split()))
if n == 0:
    print(0)
    exit()
M = max(a)
m = min(a)
max_abs = max(abs(M), abs(m))

total = 0
for num in a:
    if max_abs == abs(M):
        if abs(num) < abs(M):
            total += abs(M)
        else:
            total += abs(num)
    else:
        if num == m:
            total += abs(m)
        else:
            if abs(num) >= abs(m):
                total += abs(num)
            else:
                if abs(M) > abs(num):
                    total += abs(M)
                else:
                    total += abs(num)
print(total)