#include<bits/stdc++.h>
using namespace std;
 
void maxSubArraySum(int a[], int size)
{
    int max_so_far = INT_MIN, max_ending_here = 0,j=0,s=0,e=0;
 
    for (int i = 0; i < size; i++)
    {
        max_ending_here = max_ending_here + a[i];
        if (max_so_far < max_ending_here)
        {
            max_so_far = max_ending_here;
            s=j;
            e=i;
        }
        if (max_ending_here < 0)
        {
            max_ending_here = 0;
            j=i+1;
        }
    }
    long sm=0;
    for(int i=s;i<e;i++)
    {
        for(j=i+1;j<=e;j++)
        {
            sm=sm+a[i]*a[j];
        }
       // cout<<a[i]<<" ";
    }
    cout<<sm;
}
 
int main()
{
    int n;
    cin>>n;
    int arr[n];
    for(int i=0;i<n;i++)
    {
        cin>>arr[i];
    }
    maxSubArraySum(arr, n);
    return 0;
}