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 mod = 1000000007;
const int INF = 0x3f3f3f3f;
const double PI = acos(-1.0);
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
const int maxn = 1e5 + 10;
int n, a[maxn];
int sum[maxn], l[maxn], r[maxn];
int sta[maxn];
int mi[maxn][25], mx[maxn][25];
void rmqinit() {
  for (int i = 0; i <= n; i++) mi[i][0] = mx[i][0] = sum[i];
  int m = (int)(log(n * 1.0) / log(2.0));
  for (int i = 1; i <= m; i++)
    for (int j = 0; j <= n; j++) {
      mx[j][i] = mx[j][i - 1];
      if (j + (1 << (i - 1)) <= n)
        mx[j][i] = max(mx[j][i], mx[j + (1 << (i - 1))][i - 1]);
      mi[j][i] = mi[j][i - 1];
      if (j + (1 << (i - 1)) <= n)
        mi[j][i] = min(mi[j][i], mi[j + (1 << (i - 1))][i - 1]);
    }
}
int rmqmin(int l, int r) {
  int m = (int)(log((r - l + 1) * 1.0) / log(2.0));
  return min(mi[l][m], mi[r - (1 << m) + 1][m]);
}
int rmqmax(int l, int r) {
  int m = (int)(log((r - l + 1) * 1.0) / log(2.0));
  return max(mx[l][m], mx[r - (1 << m) + 1][m]);
}
int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(0);
  std::cout.tie(0);
  cin >> n;
  for (int i = 1; i < n + 1; i++) {
    cin >> a[i];
    sum[i] = sum[i - 1] + a[i];
  }
  int top = 0;
  for (int i = 1; i <= n; i++) {
    while (top && a[sta[top]] <= a[i]) top--;
    if (top == 0)
      l[i] = 1;
    else
      l[i] = sta[top] + 1;
    sta[++top] = i;
  }
  top = 0;
  for (int i = n; i >= 1; i--) {
    while (top && a[sta[top]] <= a[i]) top--;
    if (top == 0)
      r[i] = n;
    else
      r[i] = sta[top] - 1;
    sta[++top] = i;
  }
  rmqinit();
  int ans = 0;
  for (int i = 1; i <= n; ++i) {
    int s = rmqmin(l[i] - 1, i - 1), t = rmqmax(i, r[i]);
    ans = max(ans, t - s - a[i]);
  }
  cout << ans << '\n';
  return 0;
}
