n = int(input()) + 1
a = [0] + [int(x) for x in input().strip().split()]
b = a[:]

for i in range(1, n):
    b[i] += b[i-1]

ans = float('-inf')
for start in range(1, n):
    total = a[start]
    ans = max(ans, total)
    total = 0
    for end in range(start+1, n):
        total += (b[end-1] - b[start-1]) * a[end]
        ans = max(ans, total)

print(ans)