#include<iostream>
#include<climits>
using namespace std;
 
int maxSubArraySum(int a[], int size)
{
    int x,w,i,j,c=0;
    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;
        }
    }
    w=start;
    x=end;
    for(i=w;i<x;i++)
    {
        for(j=i+1;j<=x;j++)
        {
            c+=(a[i]*a[j]);
        }
    }
    return c;
}
int main()
{
    int i,j,k,c=0,n;
    cin>>n;
    int a[n];
    for(i=0;i<n;i++)
    {
        cin>>a[i];
    }
    int max_sum = maxSubArraySum(a, n);
    cout<<max_sum;
    return 0;
}