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 + 10;
int a[maxn], n;
long long solve(int l, int r) {
  if (r - l == 1) return 0;
  int mid = l + r >> 1;
  long long ret = solve(l, mid) + solve(mid, r);
  {
    set<int> s;
    for (int i = mid - 1, j = mid, p = 0; i >= l; i--) {
      p = max(p, a[i]);
      while (j < r && a[j] < p) s.insert(a[j++]);
      ret += s.count(p - a[i]);
    }
  }
  {
    set<int> s;
    for (int i = mid, j = mid - 1, p = 0; i < r; i++) {
      p = max(p, a[i]);
      while (j >= l && a[j] < p) s.insert(a[j--]);
      ret += s.count(p - a[i]);
    }
  }
  return ret;
}
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  printf("%lld\n", solve(0, n));
  return 0;
}
