#include<bits/stdc++.h>

using namespace std;


int main() {
    int n,i;
    cin>>n;
    int a[n];
    vector<int > v;
    
    for(i=1;i<=n;i++) cin>>a[i];
    
int max_so_far = 0, max_ending_here = 0;
   for (i =1; i <=n; i++)
   {
       max_ending_here = max_ending_here + a[i];
       if (max_ending_here < 0)
       {
           max_ending_here = 0;
            v.clear();   
       }
 
       
       else if (max_so_far < max_ending_here)
       {
           max_so_far = max_ending_here;
           v.push_back(a[i]);
       }
       else
       {
           v.push_back(a[i]);
       }
   }
   
   int sum=0;
    for(i=0;i<v.size()-1;i++)
    {
        for(int j=i+1;j<v.size();j++)
        {
            sum+=(v[i]*v[j]);
        }
    }
    cout<<sum<<endl;
    
    return 0;
}