N = int(input())
a = list(map(int,input().split()))
s = set()
s.add(a[0])
import sys
if N == 2:
    b = a[0]
    c = a[1]
    l = [b+c,b-c,b*c]
    if c != 0:
        l.append(b//c)
    print(sorted(l)[-1])
    exit()
for i in range(1,N):
    t = set()
    b = a[i]
    for v in s:
        t.add(v+b)
        t.add(v*b)
        t.add(v-b)
    s = t
print(sorted(s)[-1])