#include <bits/stdc++.h>

using namespace std;
long largestValue(vector <int> A) {
    // Return the largest value of any of A's nonempty subarrays.
    long int max_so_far=A[0],current_max=A[0];
    int start=0,end=0;
    for(int i=1;i<A.size();i++)
    {
        if(current_max<current_max+A[i])
        {
            current_max+=A[i];
            end=i;
        }
        if(current_max<A[i])
        {
            current_max=A[i];
            start=i;
        }
        if(max_so_far<current_max)
        {
            max_so_far=current_max;
            end=i;
        }
        
    }
    //cout<<start<<" "<<end<<endl;
    long int ans=0;
    int size=A.size();
    for(int i=start;i<=end;i++)
    {
    	for(int 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;
}