#include <bits/stdc++.h>

using namespace std;

long long largestValue(vector <int> A) {
    int max_so_far = INT_MIN, max_ending_here = 0,
       start =0, end = 0, s=0;
 
    for (int i=0; i< A.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;
        }
    }
    long long ans=0;
    for(int i=start;i<=end;i++)
    {
        for(int j=i+1;j<=end;j++)
            ans+=A[i]*A[j];
    }
    //cout<<start<<" "<<end<<endl;
    return ans;
}

int main() {
    int n;
    cin >> n;
    vector<int> A(n);
    for(int A_i = 0; A_i < n; A_i++){
       cin >> A[A_i];
    }
    long long result = largestValue(A);
    cout << result << endl;
    return 0;
}