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;
const int maxn = 2e5 + 5;
int p[maxn], a[maxn];
int l[maxn], r[maxn];
int main() {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    p[a[i]] = i;
  }
  r[n] = n;
  set<int> s;
  s.insert(p[n]);
  for (int i = n - 1; i >= 1; i--) {
    auto t = s.lower_bound(p[i]);
    if (t != s.end())
      r[i] = *t - 1;
    else
      r[i] = n;
    s.insert(p[i]);
  }
  s.clear();
  s.insert(-p[n]);
  l[n] = 1;
  for (int i = n - 1; i >= 1; i--) {
    auto t = s.lower_bound(-p[i]);
    if (t != s.end())
      l[i] = -*t + 1;
    else
      l[i] = 1;
    s.insert(-p[i]);
  }
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    int L = l[i], R = r[i];
    if (R - p[i] < p[i] - L) {
      for (int j = p[i] + 1; j <= R; j++) {
        if (p[i - a[j]] < p[i] && p[i - a[j]] >= L) ans++;
      }
    } else {
      for (int j = p[i] - 1; j >= L; j--) {
        if (p[i - a[j]] > p[i] && p[i - a[j]] <= R) ans++;
      }
    }
  }
  cout << ans;
}
