Alice and Bob are playing yet another card game. This time the rules are the following. There are n cards lying in a row in front of them. The i-th card has value a_i. 

First, Alice chooses a non-empty consecutive segment of cards [l; r] (l ≤ r). After that Bob removes a single card j from that segment (l ≤ j ≤ r). The score of the game is the total value of the remaining cards on the segment (a_l + a_{l + 1} + ... + a_{j - 1} + a_{j + 1} + ... + a_{r - 1} + a_r). In particular, if Alice chooses a segment with just one element, then the score after Bob removes the only card is 0.

Alice wants to make the score as big as possible. Bob takes such a card that the score is as small as possible.

What segment should Alice choose so that the score is maximum possible? Output the maximum score.

Input

The first line contains a single integer n (1 ≤ n ≤ 10^5) — the number of cards.

The second line contains n integers a_1, a_2, ..., a_n (-30 ≤ a_i ≤ 30) — the values on the cards.

Output

Print a single integer — the final score of the game.

Examples

Input


5
5 -2 10 -1 4


Output


6


Input


8
5 2 5 3 -30 -30 6 9


Output


10


Input


3
-10 6 -15


Output


0

Note

In the first example Alice chooses a segment [1;5] — the entire row of cards. Bob removes card 3 with the value 10 from the segment. Thus, the final score is 5 + (-2) + (-1) + 4 = 6.

In the second example Alice chooses a segment [1;4], so that Bob removes either card 1 or 3 with the value 5, making the answer 5 + 2 + 3 = 10.

In the third example Alice can choose any of the segments of length 1: [1;1], [2;2] or [3;3]. Bob removes the only card, so the score is 0. If Alice chooses some other segment then the answer will be less than 0.

import java.util.HashSet;
import java.util.Scanner;

public class P1359D_2 {

	private static class P1359DSolution {
		
		public int solve(int[] a) {
			int n = a.length;
			
			HashSet<Integer> set = new HashSet<>();
			
			for(int x: a) {
				set.add(x);
			}
			
			int ans = 0;
			
			for(int x: set) {
				int[] b = new int[n];
				for(int i=0; i<n; i++) {
					if (a[i]>x) {
						b[i] = -(int)1e9;
					} else {
						b[i] = a[i];
					}
				}
				int maxSum = -(int)1e9;
				int sum = 0;
				
				for(int i=0; i<n; i++) {
					sum += b[i];
					maxSum = Math.max(maxSum, sum);
					if (sum<0) {
						sum = 0;
					}
				}
//				System.out.println(x+" "+(maxSum-x));
				ans = Math.max(ans, maxSum-x);
			}
			return ans;
		}

	}

	private static Scanner in;

	private static int n;
	private static int[] a;

	public static void main(String[] args) {
		in = new Scanner(System.in);

		n = in.nextInt();
		a = new int[n];

		for (int i = 0; i < n; i++) {
			a[i] = in.nextInt();
		}

		System.out.println(new P1359DSolution().solve(a));
	}

}

//5 3 13 12 16

