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 Main	{
   static class Pair implements Comparable<Pair>{
   int a;
   int b;
   public Pair(int x,int y){a=x;b=y;}
   public Pair(){}
   public int compareTo(Pair p){
	 return p.a - a;
   }
 }
   static class cell implements Comparable<cell>{
	   int a,b;
	   long dis;
	   public cell(int x,int y,long z) {a=x;b=y;dis=z;}
	   public int compareTo(cell c) {
		   return Long.compare(dis,c.dis);
	   }
   }
static class TrieNode{
  TrieNode[]child;
  int w;
  boolean term;
  TrieNode(){
    child = new TrieNode[26];  
  }
}
  public static long gcd(long a,long b)
  {
    if(a<b)

      return gcd(b,a);
    if(b==0)
      return a;
    return gcd(b,a%b);
    
  }
  static long lcm(long a,long b) {
	  return a*b / gcd(a,b);
  }
  //static long ans = 0;
  static long mod = (long)(1e9+7);///998244353;
   
    public static void main(String[] args) throws Exception {
       new Thread(null, null, "Anshum Gupta", 99999999) {
            public void run() {
                try {
                    solve();
                } catch(Exception e) {
                    e.printStackTrace();
                    System.exit(1);
                }
            }
        }.start();
    }

static long pow(long x,long y){
    if(y == 0)return 1;
    if(y==1)return x;
    long a = pow(x,y/2);
    a = (a*a)%mod;
    if(y%2==0){
        return a;
    }
    return (a*x)%mod;
}

static long mxx;
static int mxN = (int)(3e5+5);
static long[]fact,inv_fact;
static long my_inv(long a) {
	return pow(a,mod-2);
}
static long bin(int a,int b) {
	if(a < b || a<0 || b<0)return 0;
    return ((fact[a]*inv_fact[a-b])%mod * inv_fact[b])%mod;
}
//static ArrayList<ArrayList<Integer>>adj;
//static boolean[]vis;
//static long[]dis;
//static long val;
//static void dfs(int sv,int cur) {
//	if(vis[sv]) {
//	//	dis[sv] = cur;
//		val = cur-dis[sv];
//		return;
//	}
//	vis[sv] = true;
//	dis[sv]=cur;
//	for(int x:adj.get(sv)) {
//		     
//			dfs(x,cur+1);
//		
//	}
//}
static int n,m;
static long[][]c;
static int[]x= {0,0,-1,1};
static int[]y= {-1,1,0,0};

 public static void solve() throws Exception {
   // solve the problem here
   MyScanner s = new MyScanner();
        out = new PrintWriter(new BufferedOutputStream(System.out), true);
        int tc = 1;//s.nextInt();
        mxx = (long)(1e18+5);
//       fact=new long[mxN];
//       inv_fact = new long[mxN];
//       fact[0]=inv_fact[0]=1L;
//       for(int i=1;i<mxN;i++) {
//    	   fact[i] = (i*fact[i-1])%mod;
//    	   inv_fact[i] = my_inv(fact[i]);
//       }
        while(tc-->0){
        	int n = s.nextInt();
        	int[]a=new int[n];
        	for(int i=0;i<n;++i)a[i]=s.nextInt();
        	int ans = 0;
        	for(int i=0;i<=30;i++) {
        		int cur = 0;
        		int sum = 0;
        		for(int j=0;j<n;j++) {
        			if(a[j] > i) {
        				cur = 0;
        				continue;
        			}
        			cur += a[j];
        			if(cur < 0)cur = 0;
        			ans = Math.max(ans, cur - i);
        		}
        	}
        	out.println(ans);
        	
        }
        	
           
        out.flush();
}
 
     
 
 
 
    //-----------PrintWriter for faster output---------------------------------
    public static PrintWriter out;
 
    //-----------MyScanner class for faster input----------
    public static class MyScanner {
        BufferedReader br;
        StringTokenizer st;
 
        public MyScanner() {
            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 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;
        }
    }
    //--------------------------------------------------------
}
