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.
#include <bits/stdc++.h>
using namespace std;
const long long int N = 300009;
const long long int mod = 1000000007;
void pre() {}
vector<long long int> arr;
long long int size;
long long int maxSubarrSum() {
  long long int cmx = arr[0], gmx = arr[0];
  long long int l = 0, r = 0;
  long long int tl = 0, tr = 0;
  for (long long int i = 1; i < size; i++) {
    if (cmx + arr[i] >= arr[i]) {
      cmx += arr[i];
      tr++;
    } else {
      cmx = arr[i];
      tl = tr = i;
    }
    if (gmx <= cmx) {
      gmx = cmx;
      l = tl;
      r = tr;
    }
  }
  return gmx;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin.exceptions(cin.failbit);
  ;
  pre();
  long long int n;
  cin >> n;
  vector<long long int> a(n);
  size = n;
  arr.resize(n);
  for (auto& it : a) cin >> it;
  long long int mx = 0;
  for (long long int i = 30; i >= 0; i--) {
    for (long long int j = 0; j < (n); ++j) {
      if (a[j] > i) {
        arr[j] = INT_MIN;
      } else {
        arr[j] = a[j];
      }
    }
    mx = max(mx, maxSubarrSum() - i);
  }
  cout << mx << "\n";
  return 0;
}
