N = int(input())
lsa = list(map(int,input().split()))
ko = [lsa[0]]

for i in range(1,N):
    ko1 = []
    for k in ko:
        ko1.append(k+lsa[i])
        ko1.append(k-lsa[i])
        ko1.append(k*lsa[i])
    ko1.sort()
    a = ko1[-1]
    ko1.sort(key=lambda x:abs(x))
    b = ko1[-1]
    ko = [a,b]
print(max(ko))