#include <bits/stdc++.h>
using namespace std;
pair<int,int> maxS(int a[], int size)
{
    int max_so_far = INT_MIN, max_ending_here = 0,
       start =0, end = 0, s=0;
 
    for (int i=0; i< size; i++ )
    {
        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;
        }
    }
    
     pair<int,int> p={start,end};
    return p;
}

int main() {
      int n;
    cin>>n;
    int a[n];
    for(int i=0;i<n;i++)
        cin>>a[i];
    pair<int,int> p=maxS(a,n);
    int sum=0;
    for(int i=p.first;i<p.second;i++)
        for(int j=i+1;j<=p.second;j++)
            sum+=a[i]*a[j];
    cout<<sum;
    return 0;
}