import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static long largestValue(int[] A) {
        // Return the largest value of any of A's nonempty subarrays.
         int max=Integer.MIN_VALUE;
        int sum=0;
        int min_index=0;
        int max_index=-1;
        int max_sum=0;
        
        for(int i=0;i<A.length;i++)
        {
            
            sum+=A[i];
            if(sum>max)
            {
                max=sum;
                max_index=i;
                
            }
            if(sum<0)
            {
                sum=0;
                min_index=i+1;
            }
        }
        /*System.out.println(max);
        System.out.println(min_index);
        System.out.println(max_index);
        
        /* for (int i=min_index;i<=max_index;i++)
         {
             System.out.println(A[i]);
}*/
        for (int i=min_index;i<max_index;i++)
        {
            for(int j=i+1;j<=max_index;j++)
            {
               //ystem.out.print(A[i]+" "+A[j]);
                max_sum+=A[i]*A[j];
                
                }
           //ystem.out.println(max_sum);
           //ystem.out.println();
        }
        return max_sum;
       
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] A = new int[n];
        for(int A_i = 0; A_i < n; A_i++){
            A[A_i] = in.nextInt();
        }
        long result = largestValue(A);
        System.out.println(result);
        in.close();
    }
}