#!/bin/python

import sys

def largestValue(A, n):
    # Return the largest value of any of A's nonempty subarrays.
    maxArr = [[0, 0]]*n
    B = A[:]
    
    for x in xrange(n-1):
        B[x+1]+=B[x]
    
    ind = 0    
    for x in xrange(1, n):
        if ind==0:
            if maxArr[x][0] <= maxArr[x-1][0]+A[x]*B[x-1]:
                maxArr[x][0] = maxArr[x-1][0]+A[x]*B[x-1]
            else:
                maxArr[x][1] = x
                ind = x
        else:
            if maxArr[x][0] <= maxArr[x-1][0]+A[x]*(B[x-1]-B[ind-1]):
                maxArr[x][0] = maxArr[x-1][0]+A[x]*(B[x-1]-B[ind-1])
                maxArr[x][1] = maxArr[x-1][1]
            else:
                maxArr[x][1] = x
                ind = x
           
    res = 0
    for x in xrange(n):
        if maxArr[x][0]>res:
            res = maxArr[x][0]
            
            
    return res
        

if __name__ == "__main__":
    n = int(raw_input().strip())
    A = map(int, raw_input().strip().split(' '))
    result = largestValue(A, n)
    print result