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.util.StringTokenizer;

import static java.lang.Math.*;

public class Main {

    static void run() throws IOException {
        file("", "");
//        int t = nextInt();
//        while (t-- > 0)
        solution();
        end();
    }

    static void solution() throws IOException {
        int n = nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = nextInt();
        }
        long max = 0;
        for (int mx = 1; mx <= 30; mx++) {
            long sum = 0;
            for (int j = 0; j < n; j++) {
                if (arr[j] + sum <= 0 || arr[j] > mx) {
                    sum = 0;
                    continue;
                }
                sum += arr[j];
                max = max(max, sum - mx);
            }
        }
        out.println(max);
    }

    static mem create_mem(int from, int to, int val) {
        mem y = new mem();
        y.from = from;
        y.to = to;
        y.val = val;
        return y;
    }

    static class mem {
        int from, to, val;
    }

    /**
     * Z-function
     **/
    static int[] Z_function(char[] s) {
        int[] z = new int[s.length];
        for (int i = 1, l = 0, r = 0; i < s.length; i++) {
            if (i <= r)
                z[i] = min(r - i + 1, z[i - l]);
            while (z[i] + i < s.length && s[z[i] + i] == s[z[i]])
                ++z[i];
            if (i + z[i] - 1 > r) {
                l = i;
                r = i + z[i] - 1;
            }
        }
        return z;
    }

    /**
     * Pow
     **/
    static long Pow(long a, long b) {
        long h = 1;
        while (b > 0) {
            if (b % 2 != 0) {
                h *= a;
                b--;
            }
            b /= 2;
            a *= a;
        }
        return h;
    }

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

    /**
     * gcd
     **/
    static long gcd(long a, long b) {
        return b == 0 ? a : gcd(b, a % b);
    }

    /**
     * end
     **/
    static void end() {
        out.flush();
        out.close();
        System.exit(0);
    }

    /**
     * files
     **/
    static BufferedReader br;
    static PrintWriter out;

    static void file(String input, String output) {
        if (input.equals("")) {
            br = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        } else {
            try {
                br = new BufferedReader(new FileReader(input));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
            try {
                out = new PrintWriter(output);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * inputs
     **/
    static StringTokenizer in = new StringTokenizer("");

    static String nextToken() throws IOException {
        while (in == null || !in.hasMoreTokens()) {
            String s = br.readLine();
            if (s == null) return null;
            in = new StringTokenizer(s);
        }
        return in.nextToken();
    }


    static int nextInt() throws IOException {
        return Integer.parseInt(nextToken());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(nextToken());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(nextToken());
    }

    public static void main(String[] args) throws IOException {
        run();
    }
}