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.io.*;
import java.math.BigDecimal;
import java.math.MathContext;
import java.util.*;

/*
 * @author: Ramanqul
 * */
public class Main {
    private static boolean USE_TEST_CASES = false;
    private static final double EPS = .000000001;


    private static void solve(final int testCase, MyScanner in, PrintWriter out) {
        int n = in.nextInt();
        int a[] = new int[n];
        H.readArray(in, a, n);

        int localMax = 0;
        int ans = 0;

        for (int s=30;s>=1;s--) {
            localMax = 0;
            for (int i = 0; i < n; i++) {
                if (a[i] > s) {
                    localMax = 0;
                    continue;
                }

                localMax += a[i];
                localMax = Math.max(localMax, 0);
                ans = Math.max(ans, localMax-s);
            }
        }

        out.println(ans);
    }



    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out));
        int t = 1;

        if (USE_TEST_CASES) {
            t = sc.nextInt();
        }

        for (int i=0;i<t;i++) {
            solve(i, sc, out);
        }
        out.close();
    }

    private static class Pair<A,B> {
        public A first;
        public B second;
        public Pair(A first, B second) {
            this.first = first;
            this.second = second;
        }
    }

    private static class Triple<A,B,C> {
        public A first;
        public B second;
        public C third;

        public Triple(A first, B second, C third) {
            this.first = first;
            this.second = second;
            this.third = third;
        }
    }

    private static class H {
        public static void readArray(MyScanner in, int a[], int n) {
            for (int i=0;i<n;i++) {
                a[i] = in.nextInt();
            }
        }

        public static boolean isUnique(int ... nums) {
            Set<Integer> s = new HashSet<>();
            for (int i:nums) {
                if (s.contains(i)) {
                    return false;
                }
                s.add(i);
            }

            return true;
        }


        public static Pair<Integer, Integer>[] readIntPairs(MyScanner in, int n) {
            Pair[] pairs = new Pair[n];
            for (int i=0;i<n;i++) {
                int x = in.nextInt();
                int y = in.nextInt();
                pairs[i] = new Pair<Integer, Integer>(x, y);
            }

            return pairs;
        }

        public static List<Integer> dfs(int start, List<Integer>[] adj) {
            boolean v[] = new boolean[adj.length+1];

            List<Integer> res = new ArrayList<>();

            Stack<Integer> st = new Stack<>();

            st.push(start);

            while (!st.isEmpty()) {
                int x = st.pop();
                if (!v[x]) {
                    res.add(x);
                    boolean allVisited = true;
                    for (int e: adj[x]) {
                        if (!v[e]) {
                            st.push(e);
                            allVisited = false;
                        }
                    }

                    if (allVisited) {
                        break;
                    }

                    v[x] = true;
                } else {
                    break;
                }
            }

            return res;
        }

        public static long gcd(long a, long b) {
            if (a == 0) {
                return b;
            }

            return gcd(b%a, a);
        }

        public static long lcm(long a, long b) {
            return (a * b) / gcd(a,b);
        }
    }

    private static class MyScanner {
        BufferedReader br;
        StringTokenizer st;

        public MyScanner() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public MyScanner(InputStream is) {
            br = new BufferedReader(new InputStreamReader(is));
        }

        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;
        }

    }
}