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.


# from math import factorial as fac
from collections import defaultdict
# from copy import deepcopy
import sys, math
f = None
try:
	f = open('q1.input', 'r')
except IOError:
	f = sys.stdin
if 'xrange' in dir(__builtins__):
	range = xrange
# print(f.readline())
# sys.setrecursionlimit(10**6)

	
def print_case_iterable(case_num, iterable):
	print("Case #{}: {}".format(case_num," ".join(map(str,iterable))))

def print_case_number(case_num, iterable):
	print("Case #{}: {}".format(case_num,iterable))

def print_iterable(A):
	print (' '.join(A))

def read_int():
	return int(f.readline().strip())
def read_int_array():
	return [int(x) for x in f.readline().strip().split(" ")]
def rns():
	a =  [x for x in f.readline().split(" ")]
	return int(a[0]), a[1].strip()
def read_string():
	return list(f.readline().strip())
def bi(x):
	return bin(x)[2:]





from collections import deque
import math


def regular_bs(L,x,l=None,r=None):
	l = 0 if l == None else l
	r = len(L) if r == None else r
	while (r-l) > 1:
		m = (r+l)//2
		l = m if L[m] <= x else l
		r = m if L[m] > x else r
	cnt = 0
	return l

def solution(A,n):
	total_max = 0
	d = defaultdict(list)
	elems = set(A)
	for x in elems:
		if x > 0:
			d[x].append(-1)
	for i in range(n):
		if A[i] <= 0:
			continue
		for x in range(1,A[i]):
			if x in elems:
				d[x].append(i)
	for x in elems:
		if x > 0:
			d[x].append(n)
	# print(d)
	for m in elems:
		for j in range(1,len(d[m])):
			start = d[m][j-1]+1
			end = d[m][j]
			max_so_far = 0
			max_end_here = 0
			saw_max = False
			for i in range(start,end):
				x = A[i]
				if x == m and not saw_max:
					saw_max = True
					max_so_far = max(max_so_far,max_end_here)
					continue
				max_end_here = max_end_here + x
				if saw_max:
					max_so_far = max(max_so_far,max_end_here)
				if saw_max and max_end_here <= -m or ((not saw_max) and max_end_here<=0):
					saw_max = False
					max_end_here = 0
			total_max = max(total_max,max_so_far)
	return total_max
 
			


def main():
	T = 1
	for i in range(T):
		n = read_int()
		A  = read_int_array()
	
		x = solution(A,n)

		if 'xrange' not in dir(__builtins__):
			print(x)
		else:
			print >>output,str(x)# "Case #"+str(i+1)+':',
	if 'xrange' in dir(__builtins__):
		print(output.getvalue())
		output.close()

if 'xrange' in dir(__builtins__):
	import cStringIO
	output = cStringIO.StringIO()
#example usage:
#    for l in res:
#       print >>output, str(len(l)) + ' ' +  ' '.join(l)

if __name__ == '__main__':
	main()

