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.
// package com.company;
import java.util.*;
import java.lang.*;
import java.io.*;
//****Use Integer Wrapper Class for Arrays.sort()****
public class DE4 {
    static PrintWriter out=new PrintWriter(new OutputStreamWriter(System.out));
    public static void main(String[] Args){
        FastReader scan=new FastReader();
        int t=1;
//        t=scan.nextInt();
        while(t-->0){
            int n=scan.nextInt();
            int[] arr=new int[n];
            for(int i=0;i<n;i++){
                arr[i]=scan.nextInt();
            }
            int ans=0;
            int[] ps=new int[n];
            int[] ss=new int[n];
            Stack<Pair> st=new Stack<>();
            for(int i=0;i<n;i++){
                int sum=0;
                while(!st.isEmpty()&&arr[st.peek().x]<=arr[i]){
                    int in=st.peek().x;
                    Pair cur=st.pop();
                    int temp=sum;
                    sum+=ps[in]+arr[in];
                    ps[i]=Math.max(ps[i],sum);
                    sum=temp+cur.y;
                }
                st.add(new Pair(i,sum+arr[i]));
            }
            st.clear();
            for(int i=n-1;i>=0;i--){
                int sum=0;
                while(!st.isEmpty()&&arr[st.peek().x]<=arr[i]){
                    int in=st.peek().x;
                    Pair cur=st.pop();
                    int temp=sum;
                    sum+=ss[in]+arr[in];
                    ss[i]=Math.max(ss[i],sum);
                    sum=temp+cur.y;
                }
                st.add(new Pair(i,sum+arr[i]));
            }
            for(int i=0;i<n;i++){
                int temp=0;
                if(i>0){
                    temp+=ps[i];
                }
                if(i<n-1){
                    temp+=ss[i];
                }
                ans=Math.max(ans,temp);
            }
            out.println(ans);
        }
        out.flush();
        out.close();
    }
    static class Pair{
        int x;
        int y;
        Pair(int x,int y){
            this.x=x;
            this.y=y;
        }
    }
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        public FastReader()
        {
            br = new BufferedReader(new
                    InputStreamReader(System.in));
        }

        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        int nextInt()
        {
            return Integer.parseInt(next());
        }

        long nextLong()
        {
            return Long.parseLong(next());
        }

        double nextDouble()
        {
            return Double.parseDouble(next());
        }

        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }

}
