n = int(input())
*a, = map(int,input().split())
p = n = a[0]
for x in a[1:]:
    p,n = max(p*x,p+x,p-x,n*x,n+x,n-x), min(p*x,p+x,p-x,n*x,n+x,n-x)
print(p)