You are given a permutation p of n integers 1, 2, ..., n (a permutation is an array where each element from 1 to n occurs exactly once).

Let's call some subsegment p[l, r] of this permutation special if p_l + p_r = max _{i = l}^{r} p_i. Please calculate the number of special subsegments.

Input

The first line contains one integer n (3 ≤ n ≤ 2 ⋅ 10^5).

The second line contains n integers p_1, p_2, ..., p_n (1 ≤ p_i ≤ n). All these integers are pairwise distinct.

Output

Print the number of special subsegments of the given permutation.

Examples

Input


5
3 4 1 5 2


Output


2


Input


3
1 3 2


Output


1

Note

Special subsegments in the first example are [1, 5] and [1, 3].

The only special subsegment in the second example is [1, 3].
#include <bits/stdc++.h>
using namespace std;
int n, a[200001], p[200001], l[200001], r[200001], s;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    p[a[i]] = i;
    l[i] = i - 1;
    while (l[i] > 0 && a[l[i]] <= a[i]) l[i] = l[l[i]];
  }
  for (int i = n; i > 0; i--) {
    r[i] = i + 1;
    while (r[i] <= n && a[r[i]] < a[i]) r[i] = r[r[i]];
    if (i - l[i] < r[i] - i) {
      for (int j = l[i] + 1; j <= i; j++) {
        int d = a[i] - a[j];
        if (d > 0 && d <= n && p[d] >= i && p[d] < r[i]) s++;
      }
    } else {
      for (int j = i; j < r[i]; j++) {
        int d = a[i] - a[j];
        if (d > 0 && d <= n && p[d] <= i && p[d] > l[i]) s++;
      }
    }
  }
  cout << s;
  return 0;
}
