N = int(input())
A = map(int, input().split())
A0 = next(A)
dp_min = dp_max = A0


def div_inf(x, a, inf):
    return x // a if a else inf


INF = 10 ** 18

for a in A:
    dp_min, dp_max = (
        min(
            dp_min + a, dp_max + a,
            dp_min - a, dp_max - a,
            dp_min * a, dp_max * a,
            div_inf(dp_min, a, INF), div_inf(dp_max, a, INF)
        ),
        max(
            dp_min + a, dp_max + a,
            dp_min - a, dp_max - a,
            dp_min * a, dp_max * a,
            div_inf(dp_min, a, -INF), div_inf(dp_max, a, -INF)
        ))
print(dp_max)