#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int main() {
    long long int t;
    cin>>t;
    int prod=0;
    long long int ar[t];
    for(long long int i=0;i<t;i++){
        cin>>ar[i];
    }
      int max_so_far=0,max_ending_here=0;
      int r=0;
      std::vector<int> arr(t);
 
    for (int i = 0; i < t; i++)
    {
        max_ending_here = max_ending_here + ar[i];
        if (max_so_far < max_ending_here){
            max_so_far = max_ending_here;
            arr[r] = ar[i];
             r++;
        }
 
        if (max_ending_here < 0){
            max_ending_here = 0;
            arr.clear();
            r =0;
        }
    } 
      for(int a=0;a<arr.size()-1;a++){
          for(int b=a+1;b<arr.size();b++){
              prod = prod + arr[a]*arr[b];
          }
      }
    cout<<prod;
    return 0;
}