#include <bits/stdc++.h>

using namespace std;

long largestValue(vector <int> A, int n) {
    // Return the largest value of any of A's nonempty subarrays.
    vector <int> B(n);
    long i, k;
    long j = 0;
    for(i=0;i<n;i++)
    {
        if(A[i] > 0)
        {
            B[j] = A[i];
            j++;
        }
    }
    sort(B.rbegin(), B.rend());
    int max = -1000;
    for(i=0;i<n;i++)
    {
        if((A[i]<0)  && (A[i]>max))
        {
            max = A[i];
        }
    }
 
    long sum = 0;
    long product;
    for(i=0;i<j-1;i++)
    {
        for(k=i+1;k<j;k++)
        {
            product = B[i]*B[k];
            sum += product;
        }
    }
    long sum1 = 0;
    for(i=0;i<j;i++)
    {
        sum1 += B[i];
    }
    sum1 *= max;
    sum += sum1;
    return sum;
}

int main() {
    long 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, n);
    cout << result << endl;
    return 0;
}