N = int(input())
lsa = list(map(int,input().split()))
c = -float('INF')
for i in range(2**(N-1)):
    a = lsa[0]
    for j in range(N-1):
        if (i >> j) & 1:
            a *= lsa[j+1]
        else:
            if lsa[j+1] >= 0:
                a += lsa[j+1]
            else:
                a -= lsa[j+1]
    c = max(c,a)
print(c)