#include <bits/stdc++.h>

using namespace std;



/* void kadane()
{
   

    cout << "The sum of contiguous sub-array with the largest sum is " <<
            max_so_far << endl;

    cout << "The contiguous sub-array with the largest sum is ";
    for (int i = start; i <= end; i++)
        cout << arr[i] << " ";
}*/




long largestValue(int arr[], int n) {
    
    // Return the largest value of any of A's nonempty subarrays.

     // stores maximum sum sub-array found so far
    int max_so_far = 0;

    // stores maximum sum of sub-array ending at current position
    int max_ending_here = 0;

    // stores end-points of maximum sum sub-array found so far
    int start = 0, end = 0;

    // stores starting index of a positive sum sequence
    int beg = 0;

    // traverse the given array
    for (int i = 0; i < n; i++)
    {
        // update maximum sum of sub-array "ending" at index i
        max_ending_here = max_ending_here + arr[i];

        // if maximum sum is negative, set it to 0
        if (max_ending_here < 0)
        {
            max_ending_here = 0;    // empty sub-array
            beg = i + 1;
        }

        // update result if current sub-array sum is found to be greater
        if (max_so_far < max_ending_here)
        {
            max_so_far = max_ending_here;
            start = beg;
            end = i;
        }
    }
    
    
    int tmp,sum=0;
     for (int i = start; i <= end; i++)
     {
         tmp=arr[i];
         for(int j=i+1;j<=end;j++ )
         {
             sum+=tmp*arr[j];
         }
     }
    return sum;
    
}

int main() {
    int n;
    cin >> n;
    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;
}