#include <bits/stdc++.h>
using namespace std;

long maxSubArraySum(long a[], long size)
{
    long max_so_far = INT_MIN, max_ending_here = 0,sum=0,
       start =0, end = 0, s=0,i,j;
 
    for ( 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;
        }
    }
    for(i=start;i<end;i++)
    {
         for(j=i+1;j<=end;j++)
         {
             sum+=a[i]*a[j];
         }
    }
    return sum;
}

int main() {
   long  n,i;
    cin>>n;
    long a[n];
    for(i=0;i<n;i++)
    {
        cin>>a[i];
    }
    cout<<maxSubArraySum(a,n);
    return 0;
}