#include <bits/stdc++.h>

using namespace std;

long largestValue(vector <int> A) {
    // Return the largest value of any of A's nonempty subarrays.
    long max_so_far = INT_MIN;
    long ans = 0;
    long start = 0;
    long end = 0;
    for (long i = 0; i < A.size(); i++){
        ans += A[i];
        if (max_so_far < ans){
            max_so_far = ans;
            end = i;
        }
        if (ans < 0){
            ans = 0;
            start = i+1;
        }
    }
    ans = 0;
    for (long i = start; i <= end; i++){
        for (long j = i + 1; j <= end; j++){
            ans += A[i]*A[j];
        }
    }
    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 result = largestValue(A);
    cout << result << endl;
    return 0;
}