from itertools import pairwise


def accum_dp(xs: list, f, op, e, init: dict):
    dp = init.copy()
    for x in xs:
        pp = {}
        dp, pp = pp, dp
        for fm_key, fm_val in pp.items():
            for to_key, to_val in f(fm_key, fm_val, x):
                dp[to_key] = op(dp.get(to_key, e), to_val)

    return dp


def div(a, b):
    if (a < 0) ^ (b < 0):
        return -(-a // b)

    return a // b


def f(k, v, x):
    # k : 計算結果

    yield k+x, True
    yield k-x, True
    yield k*x, True

    if x != 0:
        yield div(k, x), True


INF = 1 << 62
N = int(input())
A = list(map(int, input().split()))

init = {A[0]: True}
dp = accum_dp(A[1:], f, max, -INF, init)

ans = max(dp.keys())
print(ans)