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.util.*;
import java.io.*;
import java.math.BigInteger;
 public class Solution
{
     static class Pair<A,B>
     {
        A parent;
        B rank;
        Pair(A parent,B rank)
        {
            this.rank=rank;
            this.parent=parent;
        }
    }
     static class Node{
         int x;
         int y;
         Node(int i,int j)
         {
             x=i;
             y=j;
         }
     }
     static int m=998244353;
     static ArrayList<Integer> graph[];
     static boolean visited[];
     static int fact[];
    public static void main (String[] args) throws IOException
    {
        StringBuilder sb = new StringBuilder();
        FastReader s1 = new FastReader();
        int n=s1.I();
        int ar[] = new int[n];
        for(int i=0;i<n;i++)
        {
            ar[i]=s1.I();
        }
        long ans=0;
        for(int i=1;i<=30;i++)
        {
            long curr=0;
            for(int p:ar)
            {
                curr+=p;
                if(p>i)
                {
                    curr=0;
                }
                curr=Math.max(0, curr);
                ans=Math.max(ans, curr-i);
            }
        }
        System.out.println(ans);
    }
    static long sum(long a)
    {
        return (a*(a+1))/2;
    }
    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 I()
        {
            return Integer.parseInt(next());
        }
        
        long L()
        {
            return Long.parseLong(next());
        }
        
        double D()
        {
            return Double.parseDouble(next());
        }
        
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }
    }
    static long gcd(long a,long b)
    {
        if(a%b==0)
            return b;
        return gcd(b,a%b);
    }
    static float power(float x, int y)
    {
        float temp;
        if( y == 0)
            return 1;
        temp = power(x, y/2);
        
        if (y%2 == 0)
            return temp*temp;
        else
        {
            if(y > 0)
                return x * temp * temp;
            else
                return (temp * temp) / x;
        }
    }
    static long pow(long x, long y)
    {
        long res = 1;
        x = x % m;
        if(x<0)
            x+=m;
        while (y > 0)
        {
            if((y & 1)==1){
                res = (res * x) % m;
                if(res<0)
                    res+=m;
            }
            y = y >> 1;
            x = (x * x) % m;
            if(x<0)
                x=x+m;
        }
        res=res%m;
                if(res<0)
                    res+=m;
        return res;
    }
    static void sieveOfEratosthenes(int n)
    {
        ArrayList<Integer> prime=new ArrayList<Integer>();
        boolean Prime[] = new boolean[n+1];
        for(int i=2;i<n;i++)
            Prime[i] = true;
        
        for(int p = 2; p*p <=n; p++)
        {
            if(Prime[p] == true)
            {
                prime.add(p);
                for(int i = p*p; i <= n; i += p)
                    Prime[i] = false;
            }
        }
    }
}