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 = 200007;
int n, a[MAXN], p[MAXN];
set<int> done;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
    p[a[i]] = i;
  }
  done.insert(0);
  done.insert(n + 1);
  int ans = 0;
  for (int x = n; x >= 3; --x) {
    int m = p[x], l, r;
    auto it = done.upper_bound(m);
    r = (*it);
    --it;
    l = (*it);
    if (m - l < r - m) {
      for (int i = l + 1; i <= m - 1; ++i) {
        int j = p[x - a[i]];
        if (m < j && j < r) ++ans;
      }
    } else {
      for (int i = m + 1; i <= r - 1; ++i) {
        int j = p[x - a[i]];
        if (l < j && j < m) ++ans;
      }
    }
    done.insert(m);
  }
  cout << ans << endl;
  return 0;
}
