n = int(input())
a = list(map(int,input().split(' ')))

i = 0
while i < n and a[i] == 0: i += 1
if i == n:
    print(0)
    exit(0)
ans = abs(a[i])
i += 1
for x in a[i:]:
    if x in [0,1]:
        ans += x
    else:
        ans *= abs(x)
print(ans)