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.

// Imports
import java.util.*;
import java.io.*;

public class D1359 {

    /**
     * @param args the command line arguments
     * @throws IOException, FileNotFoundException 
     */
    public static void main(String[] args) throws IOException, FileNotFoundException {
        
        // TODO UNCOMMENT WHEN ALGORITHM CORRECT
        BufferedReader f = new BufferedReader(new InputStreamReader(System.in));
        
        
        // TODO code application logic here
        
        // total "score" -> segment sum - maximum value
        // Sweep: Best result ending at x, then find maximum?
        // Issue is that the maximum value will be removed
        
        // read sol, use kadane's but with maximum value removed
        
        int N = Integer.parseInt(f.readLine());
        int[] arr = new int[N];
        
        StringTokenizer st = new StringTokenizer(f.readLine());
        int max = -31;
        for(int i = 0; i < N; i++) {
            arr[i] = Integer.parseInt(st.nextToken());
            
            if(arr[i] > max) {
                max = arr[i];
            }
        }
        
        int maxtotal = 0;
        
        for(int curr = 0; curr <= max; curr++) {
            // Run Kadane's
            int max_ending_here = 0;
            int currmax = 0;
            
            for(int i = 0; i < N; i++) {
                if(arr[i] > curr) {
                    max_ending_here = 0;
                }
                else {
                    max_ending_here = Math.max(arr[i], max_ending_here + arr[i]);
                }
                
                currmax = Math.max(currmax, max_ending_here);
            }
            
            maxtotal = Math.max(maxtotal, currmax - curr);
        }
        
        System.out.println(maxtotal);
        
        
    }

}
