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

public class Solution {

    static long largestValue(int[] A) {
    int l=A.length;
    int msf=A[0];
    int meh=0;
    int start=0,end=0,s=0;long sum=0;
    for(int i=0;i<l;i++)
    {
	   meh=meh+A[i];
	   if(msf<meh)
	   {
		msf=meh;
		start=s;
		end=i;
	}
	if(meh<0)
	{
		meh=0;
		s=i+1;
		}
}
       for(int i=start;i<end;i++){
           for(int j=i+1;j<=end;j++){
               //System.out.println(A[i]+" "+ A[j]);
               sum=sum+(A[i]*A[j]);
           }
       } 
        //System.out.println(msf+" "+start+" "+end);
        return 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();
    }
}