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;
using pll = pair<long long, long long>;
long long gcd_helper(long long a, long long b) {
  if (a % b == 0)
    return b;
  else
    return gcd_helper(b, a % b);
}
long long gcd(long long a, long long b) {
  if (a < 0) a *= -1;
  if (b < 0) b *= -1;
  if (a < b) swap(a, b);
  if (b == 0) return a;
  return gcd_helper(a, b);
}
long long powr(long long a, long long b, long long M) {
  if (b == 0) return 1;
  if (a == 0) return 0;
  long long ret = 1;
  while (b) {
    if (b & 1) {
      ret *= a;
      ret %= M;
    }
    a = (a * a) % M;
    b /= 2;
  }
  return ret;
}
long long find(long long x, vector<long long> &p) {
  if (p[x] != x) p[x] = find(p[x], p);
  return p[x];
}
void unite(long long x, long long y, vector<long long> &p,
           vector<long long> &sz) {
  long long px = find(x, p);
  long long py = find(y, p);
  if (sz[px] < sz[py]) {
    swap(px, py);
    swap(x, y);
  }
  p[py] = px;
  sz[px] += sz[py];
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n;
  cin >> n;
  vector<long long> a(n);
  for (long long i = 0; i < (n); i++) cin >> a[i];
  long long ans = 0;
  long long maxi = 30, maxsum = 0, maxtilli = 0;
  while (maxi > 0) {
    maxsum = 0;
    maxtilli = 0;
    for (long long i = 0; i < (n); i++) {
      if (a[i] > maxi) {
        maxtilli = 0;
        continue;
      }
      maxtilli = a[i] + max(0LL, maxtilli);
      maxsum = max(maxsum, maxtilli);
    }
    ans = max(ans, maxsum - maxi);
    maxi--;
  }
  cout << ans << endl;
  return 0;
}
