#!/bin/python3

from sys import maxsize
import sys
def maxSubArraySum(a,size):
    max_so_far = -maxsize - 1
    max_ending_here = 0
    start = 0
    end = 0
    s = 0
 
    for i in range(0,size):
 
        max_ending_here += a[i]
 
        if max_so_far < max_ending_here:
            max_so_far = max_ending_here
            start = s
            end = i
 
        if max_ending_here < 0:
            max_ending_here = 0
            s = i+1
 
    
    return A[start:end+1]
def pro(A):
    a = maxSubArraySum(A,len(A))
    #print(a)
    su =0
    #print(a)
    for k in range(len(a)):
        for l in range(k+1,len(a)):
            #print(a[k],a[l])
            su+=(a[k]*a[l])
    #print(su)
    return su
def largestValue(A):
    # Return the largest value of any of A's nonempty subarrays.
    
    return pro(A)
                

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