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.*;
import java.io.*;
public class EdD {

	public static void main(String[] args) throws Exception{
		int num = 998244353;

		// TODO Auto-generated method stub
 		BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
 		PrintWriter out = new PrintWriter(System.out);
//	 		String input1 = bf.readLine().trim();
//	 		String input2 = bf.readLine().trim();
	 		int n = Integer.parseInt(bf.readLine());
	 		ArrayList<Integer> array = new ArrayList<Integer>();
	 		long[] temparray = new long[n];
	 		StringTokenizer st = new StringTokenizer(bf.readLine());
	 		for(int j =0;j<n;j++){
	 			array.add(Integer.parseInt(st.nextToken()));
	 			temparray[j] = array.get(j);
	 		}
	 		long ans = Integer.MIN_VALUE;
	 		for(int j = -30;j<=30;j++){
	 			for(int k = 0;k<n;k++)
	 				if (temparray[k] > j)
	 					temparray[k] = Integer.MIN_VALUE;		
	 			long maxsum = Integer.MIN_VALUE;
	 			long currsum = 0;
	 			long[] kadane = new long[n+1];
	 			for(int k = 0;k<n;k++){
	 				kadane[k] = Math.max(currsum + temparray[k], temparray[k]);
	 				currsum = kadane[k];
	 				if (kadane[k] > maxsum)
	 					maxsum = kadane[k];
	 			}
	 			if (maxsum-j > ans){
	 				ans = maxsum-j;
	 			}
	 			for(int k = 0;k<n;k++)
	 				temparray[k] = array.get(k);
	 			
	 		}
	 		out.println(ans);
 		
 		out.close();
 		
 		
 		
 	}
}
 	
 
//StringJoiner sj = new StringJoiner(" "); 
//sj.add(strings)
//sj.toString() gives string of those stuff w spaces or whatever that sequence is

 		
 		
 		
 		
	


