import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;

/**
 * @author avAnkyAnkit last modified @02-Feb-2018 @9:01:33 PM HourRank - TODO
 */

 class q3 {

	public static void main(String[] args) throws Exception {
		solve();
	}

	// **SOLUTION**
	public static void solve() throws Exception {
		// your code goes here
		int n = sc.nextInt();
		int[] arr = new int[n];
		for (int i = 0; i < arr.length; i++) {
			arr[i] = sc.nextInt();
		}
		long maxsum = Integer.MIN_VALUE;
		for (int i = 0; i < arr.length; i++) {
			for (int j = i + 1; j < arr.length; j++) {
				maxsum = Math.max(maxsum, fun(arr, i, j));
			}
		}
		System.out.println(maxsum);
	}

	public static long fun(int[] arr, int si, int ei) {
		if (si == ei)
			return arr[si];
		long sum = 0;
		long eleTaken = 0;
		for (int i = si; i <= ei; i++) {
			sum += eleTaken * arr[i];
			eleTaken += arr[i];
		}
		return sum;
	}

	public static InputStreamReader r = new InputStreamReader(System.in);

	public static BufferedReader br = new BufferedReader(r);

	public static Scanner sc = new Scanner(System.in);

}