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 a[200005], pos[200005];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]), pos[a[i]] = i;
  set<int> cur;
  cur.insert(0);
  cur.insert(n + 1);
  int ans = 0;
  for (int i = n; i >= 1; i--) {
    int p = pos[i];
    int l = *(--cur.lower_bound(p));
    int r = *cur.lower_bound(p);
    if (p - l <= r - p) {
      for (int j = l + 1; j < p; j++)
        if (p < pos[i - a[j]] && pos[i - a[j]] < r) ans++;
    } else {
      for (int j = p + 1; j < r; j++)
        if (l < pos[i - a[j]] && pos[i - a[j]] < p) ans++;
    }
    cur.insert(p);
  }
  printf("%d\n", ans);
}
