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.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.*;

public class Run {
    static InputReader in = new InputReader(System.in);
    static PrintWriter pw = new PrintWriter(System.out);
    static long mod =   998244353L;
    static long inf = (long) -1e8;

    public static void main(String args[]) {

        int t = 1;
//        t = in.nextInt();
        for(int i = 1; i <= t ;i ++) {
            solve();
        }
        pw.flush();
        pw.close();
    }

    private static void solve() {

        int n = in.nextInt();

        long a[] = new  long[n+1];
        for(int i = 0; i  < n ; i++) {
            a[i] = in.nextLong();
        }
        long ans = 0;

        for(int i = -30; i <= 30; i++) {
            ans = Math.max(ans,maxSubArraySum(a,i));
        }
        pw.print(ans);
    }

    static long maxSubArraySum(long a[], long x)
    {
        int size = a.length;
        long max_so_far = Integer.MIN_VALUE, max_ending_here = 0;

        for (int i = 0; i < size; i++)
        {
            max_ending_here = max_ending_here + ((a[i] > x) ? inf : a[i]);

            if (max_so_far < max_ending_here)
                max_so_far = max_ending_here;
            if (max_ending_here < 0){
                max_ending_here = 0;
            }
        }
        return Math.max(0l,max_so_far-x);
    }

    private static long ncr(long n, long k, long[] fact) {
        if(n < k) return  0;
        long ret = fact[(int)n];
        ret = (ret * pow(fact[(int)(n-k)], mod-2, mod)) % mod;
        ret = (ret * pow(fact[(int)(k)], mod-2, mod)) % mod;

        return ret;

    }

    private static long pow(long a, long b, long mod) {
        if(b == 0) return 1;
        if(b == 1) return a % mod;
        long t = pow(a,b/2, mod);
        t  = (t * t) % mod;
        if(b%2!=0) {
            t = ( t * a) % mod;
        }
        return t;
    }

    static class InputReader {

        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int snext() {
            if (snumChars == -1)
                throw new InputMismatchException();
            if (curChar >= snumChars) {
                curChar = 0;
                try {
                    snumChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (snumChars <= 0)
                    return -1;
            }
            return buf[curChar++];
        }

        public int nextInt() {
            int c = snext();
            while (isSpaceChar(c)) {
                c = snext();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long nextLong() {
            int c = snext();
            while (isSpaceChar(c)) {
                c = snext();
            }
            int sgn = 1;
            if (c == '-') {
                sgn = -1;
                c = snext();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = snext();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public int[] nextIntArray(int n) {
            int a[] = new int[n];
            for (int i = 0; i < n; i++) {
                a[i] = nextInt();
            }
            return a;
        }

        public String readString() {
            int c = snext();
            while (isSpaceChar(c)) {
                c = snext();
            }
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = snext();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public String nextLine() {
            int c = snext();
            while (isSpaceChar(c))
                c = snext();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = snext();
            } while (!isEndOfLine(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if (filter != null)
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        private boolean isEndOfLine(int c) {
            return c == '\n' || c == '\r' || c == -1;
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }


    private static int[] bfs(ArrayList<Integer>[] g, int a, int n) {
        int dist[] = new int[n + 1];
        for (int i = 0; i < n + 1; i++) {
            dist[i] = n + 10;
        }
        Queue<Integer> q = new LinkedList<>();
        boolean vis[] = new boolean[n + 1];
        dist[a] = 0;
        q.add(a);
        while (!q.isEmpty()) {
            int p = q.poll();
            if (vis[p] == true) {
                continue;
            }
            vis[p] = true;
            for (Integer i : g[p]) {
                if (!vis[i]) {
                    dist[i] = Integer.min(dist[i], dist[p] + 1);
                    q.add(i);
                }
            }
        }
        return dist;
    }


}
