#include <bits/stdc++.h>

using namespace std;

long largestValue(vector <int> arr) {
	// stores maximum sum sub-array found so far
	int max_so_far = 0;
int n  = arr.size();
 	int max_ending_here = 0;

 	int start = 0, end = 0;

 	int beg = 0;

 	for (int i = 0; i < n; i++)
	{
 		max_ending_here = max_ending_here + arr[i];

 		if (max_ending_here < 0)
		{
			max_ending_here = 0;
			beg = i + 1;
		}

 		if (max_so_far < max_ending_here)
		{
			max_so_far = max_ending_here;
			start = beg;
			end = i;
		}
	}

 
int sum = 0 ;
 	for (int i = start; i <= end; i++)
for (int j =  i+1 ; j <=end ; j++)
	sum = sum + (arr[i]*arr[j]);

	return sum ;
}

int main() {
	int n;
	cin >> n;
	vector<int> A(n);
	for(int A_i = 0; A_i < n; A_i++){
		cin >> A[A_i];
	}
	long result = largestValue(A);
	cout << result << endl;
	return 0;
}