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.
// Working program with FastReader
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class d
{
    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;
        }
    }

    //        long start = System.currentTimeMillis();
//        long end = System.currentTimeMillis();
//        System.out.println((end - start) + "ms");
    public static void main(String[] args)
    {
        FastReader s=new FastReader();
//        int t = s.nextInt();
//        for(int tt=0;tt<t;tt++){
            int n = s.nextInt();
            int[] arr = new int[n];
            for(int i=0;i<n;i++){
                arr[i] = s.nextInt();
            }
            System.out.println(max_sum(n,arr));
//        }

    }
    public static int max_sum(int n,int[] arr){
        HashMap<Integer, ArrayList<Integer>> hm = new HashMap<>();
        for(int i=0;i<n;i++){
            if(!hm.containsKey(arr[i])){
                ArrayList<Integer> al = new ArrayList<>();
                al.add(i);
                hm.put(arr[i],al);
            }
            else {
                ArrayList<Integer> al = hm.get(arr[i]);
                al.add(i);
                hm.replace(arr[i],al);
            }
        }
        int max_sum = Integer.MIN_VALUE;
        int start =30;
        int[] temp_array = arr.clone();
        while (start > 0) {
            if(!hm.containsKey(start)){
                start--;
                continue;
            }
            else {
                int temp_sum = kadanesAlgo(n,temp_array);
                temp_sum-=start;
                if(temp_sum>max_sum){
                    max_sum = temp_sum;
                }
                ArrayList<Integer> positions = hm.get(start);
                for(int a:positions){
                    temp_array[a] = -100;
                }
                start--;
            }
        }
        if(max_sum>=0){
            return max_sum;
        }
        return 0;

    }

    public static int kadanesAlgo(int n,int[] arr){
        int max_so_far = Integer.MIN_VALUE;
        int max_ending_here = 0;
        for(int i=0;i<n;i++){
            max_ending_here = max_ending_here+arr[i];
            if(max_ending_here<0){
                max_ending_here =0;
            }
            else if(max_ending_here>max_so_far){
                max_so_far = max_ending_here;
            }
        }
        return max_so_far;
    }


    public static void debug(long[][] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(Arrays.toString(arr[i]));
        }
    }
    public static void debug(int[][] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(Arrays.toString(arr[i]));
        }
    }
    public static void debug(String[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.println(arr[i]);
        }
    }

    public static void print(int[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }
    public static void print(String[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }
    public static void print(long[] arr){
        int len = arr.length;
        for(int i=0;i<len;i++){
            System.out.print(arr[i]+" ");
        }
        System.out.print('\n');
    }






}
