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 f[200005], p[200005];
long long ans = 0;
void dnc(int start, int end) {
  if (start + 1 >= end) return;
  int mid = (start + end) >> 1;
  int r = mid, maxi = 0;
  int mm = 0;
  for (int i = mid + 1; i <= end; i++) {
    mm = max(mm, p[i]);
    while (r >= start && maxi <= mm) {
      maxi = max(maxi, p[r]);
      r--;
    }
    if (r < f[mm - p[i]] && f[mm - p[i]] <= mid) {
      ans++;
    }
  }
  maxi = mm = 0;
  r = mid + 1;
  for (int i = mid; i >= start; i--) {
    mm = max(mm, p[i]);
    while (r <= end && maxi < mm) {
      maxi = max(maxi, p[r]);
      r++;
    }
    if (mid + 1 <= f[mm - p[i]] && f[mm - p[i]] < r) {
      ans++;
    }
  }
  dnc(start, mid);
  dnc(mid + 1, end);
}
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &p[i]);
    f[p[i]] = i;
  }
  dnc(1, n);
  printf("%d\n", ans);
  return 0;
}
