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 N = 200005;
const int inf = 1000 * 1000 * 1000;
const int mod = 1000 * 1000 * 1000 + 7;
int n;
int a[N];
long long answ = 0;
int mx[N];
bool used[N];
void solve(int s, int e) {
  if (s == e) {
    return;
  }
  int m = (s + e) / 2;
  solve(s, m);
  solve(m + 1, e);
  for (int step = 0; step < 2; step++) {
    for (int i = m + 1; i <= e; i++) {
      mx[i] = (i == m + 1) ? a[i] : max(a[i], mx[i - 1]);
      used[a[i]] = false;
    }
    int it = m + 1, M = 0;
    for (int i = m; i >= s; i--) {
      M = (i == m) ? a[i] : max(M, a[i]);
      while (it <= e && mx[it] < M) {
        used[a[it]] = true;
        ++it;
      }
      int x = M - a[i];
      if (used[x]) {
        ++answ;
      }
    }
    for (int i = m + 1; i <= e; i++) {
      used[a[i]] = false;
    }
    reverse(a + s, a + e + 1);
    m = e - 1 - m + s;
  }
}
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  solve(1, n);
  cout << answ << endl;
  return 0;
}
