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 S {
  int a, b;
  S() {}
  S(int _a, int _b) {
    a = _a;
    b = _b;
  }
  const bool operator<(const S &o) const { return a < o.a; }
};
string exm;
inline void exf(void) {
  cout << exm << "\n";
  exit(0);
}
template <typename T>
inline void showAll(vector<T> &v, string sep = "") {
  for (T &here : v) cout << here << sep;
}
template <typename T>
inline void showAll(T a[], int st, int end, string sep = "") {
  for (int i = st; i <= end; i++) cout << a[i] << sep;
}
template <typename T>
inline void showAll(T a[], int x, int y, int z, int w, string p, string q) {
  for (int i = x; i <= y; i++) {
    for (int j = z; j <= w; j++) {
      cout << a[i][j] << p;
    }
    cout << q;
  }
}
template <typename T>
inline vector<int> int_seperation(T N, int d = 10) {
  vector<int> v;
  while (N) {
    v.push_back(N % d);
    N /= d;
  }
  reverse(v.begin(), v.end());
  return v;
}
const int SIZE = 100009;
int psum[SIZE], arr[SIZE];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &arr[i]);
    psum[i] = psum[i - 1] + arr[i];
  }
  int ans = 0;
  for (int i = 30; i >= -30; i--) {
    int mn = 0;
    for (int j = 1; j <= n; j++) {
      if (arr[j] > i)
        mn = psum[j];
      else {
        ans = max(ans, psum[j] - mn - i);
        mn = min(mn, psum[j]);
      }
    }
  }
  printf("%d\n", ans);
  return 0;
}
