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;
struct RMQ {
  const static int LOG = 19;
  int f[(1 << LOG) + 100][LOG];
  void init(int* a, int n) {
    for (int i = 0; i < n; i++) {
      f[i][0] = a[i];
    }
    for (int j = 1; j < LOG; j++) {
      for (int i = 0; i < n; i++) {
        f[i][j] = std::min(f[i][j - 1], f[i + (1 << (j - 1))][j - 1]);
      }
    }
  }
  void init(vector<int>& a, int n) {
    int tmp[n];
    std::copy(a.begin(), a.end(), tmp);
    init(tmp, n);
  }
  int get(int l, int r) {
    int d = log2(r - l + 1);
    int res = std::min(f[l][d], f[r - (1 << d) + 1][d]);
    return res;
  }
} rmq;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long test = 1;
  while (test--) {
    int n = 0;
    cin >> n;
    vector<int> a(n + 1);
    for (int i = 0; i < n; i++) cin >> a[i];
    int res = 0;
    vector<int> s(n + 1);
    for (int i = 0; i < n; i++) {
      s[i + 1] = s[i] + a[i];
    }
    rmq.init(s, n + 1);
    vector<int> lst(100, -1);
    for (int i = 0; i < n; i++) {
      lst[a[i] + 30] = i;
      int x = -1;
      for (int j = 60; j >= 0; j--) {
        int p = lst[j];
        if (p == -1) continue;
        if (x > p) continue;
        res = max(res, s[i + 1] - (j - 30) - rmq.get(x + 1, p));
        x = p;
      }
    }
    cout << res << endl;
  }
  return 0;
}
