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.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.*;
public class AnotherTask{
	public static void main(String[] args) throws IOException{
		FastReader sc = new FastReader();
		BufferedWriter out = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(java.io.FileDescriptor.out),"ASCII"),512);
		int n = sc.nextInt();
		int[] a = new int[n];
		int max = 0;
		for(int i=0;i<n;i++){
			a[i] = sc.nextInt();
			max = Math.max(a[i],max);
		}
		if(max == 0) out.write(0 + "");
		else{
			long all_max = 0l;
			for(int i=1;i<31;i++){
				int d = 0;
				long curr_max = 0l;
				long best = 0l;
				for(int j=0;j<n;j++){
					int temp  = (a[j]>i) ? Integer.MIN_VALUE : a[j];
					curr_max = curr_max+temp;
					best = Math.min(best,curr_max);
					all_max = Math.max(((curr_max-best)-i),all_max);
				}
			}
			out.write(all_max + "");
		}
		out.write('\n');
		out.flush();
	}
}
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 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; 
    }
}