// C++ program to print largest contiguous array sum
#include<iostream>
#include<climits>
using namespace std;
 
 long int maxSubArraySum(long int a[], long int size)
{
   long int max_so_far = INT_MIN, max_ending_here = 0,ans=0,start =0, end = 0, s=0;
    for (long 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;
        }
    }
       
   for(long int i=start;i<end;i++)
   	for(long int j=i+1;j<=end;j++)
     ans=ans+((a[i])*(a[j]));
   
   return ans;
   }
 int main()
{
	long int n,i;
	cin>>n;long int a[n];
	for(i=0;i<n;i++)
	cin>>a[i];
    cout<< maxSubArraySum(a, n);
    return 0;
}