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.*;
import java.math.*;

public class D {
    static final boolean RUN_TIMING = false;
    static PushbackReader in = new PushbackReader(new BufferedReader(new InputStreamReader(System.in)), 1024);
    static PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

    public void go() throws IOException {
        // in = new PushbackReader(new BufferedReader(new FileReader(new File("test.txt"))), 1024);
        // out = new PrintWriter(new FileWriter(new File("output.txt")));
        int n = ipar();
        int[] arr = iapar(n);
        int[][] prefix = new int[n][61];
        int[][] suffix = new int[n][61];
        for (int i = -30; i <= 30; i++) {
            prefix[0][i+30] = arr[0] <= i ? Math.max(arr[0], 0) : 0;
        }
        for (int i = 1; i < n; i++) {
            for (int e = -30; e <= 30; e++) {
                if (arr[i] <= e) {
                    prefix[i][e+30] = Math.max(0, prefix[i-1][e+30] + arr[i]);
                } else {
                    prefix[i][e+30] = 0;
                }
            }
        }
        for (int i = -30; i <= 30; i++) {
            suffix[n-1][i+30] = arr[n-1] <= i ? Math.max(arr[n-1], 0) : 0;
        }
        for (int i = n-2; i >= 0; i--) {
            for (int e = -30; e <= 30; e++) {
                if (arr[i] <= e) {
                    suffix[i][e+30] = Math.max(0, suffix[i+1][e+30] + arr[i]);
                } else {
                    suffix[i][e+30] = 0;
                }
            }
        }
        long best = 0;
        for (int i = 0; i < n; i++) {
            long sum = 0;
            if (i > 0) {
                sum += prefix[i-1][arr[i]+30];
            }
            if (i < n-1) {
                sum += suffix[i+1][arr[i]+30];
            }
            best = Math.max(best, sum);
        }
        // out.println(Arrays.toString(dp));
        // out.println(Arrays.toString(max));
        out.println(best);
    }

    public int ipar() throws IOException {
        return Integer.parseInt(spar());
    }

    public int[] iapar(int n) throws IOException {
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = ipar();
        }
        return arr;
    }

    public long lpar() throws IOException {
        return Long.parseLong(spar());
    }

    public long[] lapar(int n) throws IOException {
        long[] arr = new long[n];
        for (int i = 0; i < n; i++) {
            arr[i] = lpar();
        }
        return arr;
    }

    public double dpar() throws IOException {
        return Double.parseDouble(spar());
    }

    public String spar() throws IOException {
        StringBuilder sb = new StringBuilder(1024);
        int c;
        do {
            c = in.read();
        } while (Character.isWhitespace(c) && c != -1);
        if (c == -1) {
            throw new NoSuchElementException("Reached EOF");
        }
        do {
            sb.append((char)c);
            c = in.read();
        } while (!Character.isWhitespace(c) && c != -1);
        while (c != '\n' && Character.isWhitespace(c) && c != -1) {
            c = in.read();
        }
        if (c != -1 && c != '\n') {
            in.unread(c);
        }
        return sb.toString();
    }

    public String linepar() throws IOException {
        StringBuilder sb = new StringBuilder(1024);
        int c;
        while ((c = in.read()) != '\n' && c != -1) {
            if (c == '\r') {
                continue;
            }
            sb.append((char)c);
        }
        return sb.toString();
    }

    public boolean haspar() throws IOException {
        String line = linepar();
        if (line.isEmpty()) {
            return false;
        }
        in.unread('\n');
        in.unread(line.toCharArray());
        return true;
    }

    public static void main(String[] args) throws IOException {
        long time = 0;
        time -= System.nanoTime();
        new D().go();
        time += System.nanoTime();
        if (RUN_TIMING) {
            System.out.printf("%.3f ms%n", time/1000000.0);
        }
        out.flush();
        in.close();
    }
}
