#include <bits/stdc++.h>

using namespace std;

long largestValue(vector <int> A,int n,int start,int end) {
    // Return the largest value of any of A's nonempty subarrays.
    long sum=0;
    int i,j;
    for(i=start;i<=end;i++)
    {
        for(j=i+1;j<=end;j++)
        {
            sum+=(A[i]*A[j]);
        }
    }
    return sum;
}


int main() {
    int n;
    cin >> n;
    vector<int> A(n);
    for(int A_i = 0; A_i < n; A_i++){
       cin >> A[A_i];
    }
 
        int start=0,end=0,curr_max=0,prev_max=0,start_o=0,i,ts=0,te=0;


        prev_max = A[0];

        for(i=0; i<n; i++){
            curr_max += A[i];
            if(curr_max < 0){
                start = i+1;
                curr_max = 0;
            }
            else if(curr_max > prev_max){
                end = i;
                start_o = start;
                prev_max = curr_max;
            }

        }
    
      //  cout<<start_o<<end;
      //  printf("%d %d \n",start_o,end); 

    long result = largestValue(A,n,start_o,end);
    cout << result << endl;
    return 0;
}