#!/bin/python3

import sys

dp = [0]

def largestValue(A):
    # Return the largest value of any of A's nonempty subarrays.
    global dp
    n = len(A)
    dp += [A[0] * A[1]]
    
    rsum = A[0] + A[1]
    for i in range(2, n):
        dp += [dp[-1] + rsum * A[i]]
        rsum += A[i]
    
    #select maximum
    i = dp.index(max(dp))
    rsum = 0
    for j in range(i + 1):
        rsum += A[j]
    res = max(dp)
    dp2 = max(dp)
    for j in range(0, i):
        
        rsum -= A[j]
        dp2 -= A[j] * rsum
        
        res = max(dp2, res)
        
    return res
    
if __name__ == "__main__":
    n = int(input().strip())
    A = list(map(int, input().strip().split(' ')))
    result = largestValue(A)
    print(result)