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 n;
int p[200005], ind_of[200005], l_max[200005], r_max[200005];
int solve(int l, int r) {
  if (l == r) return 0;
  int ans = 0;
  int m = l + (r - l) / 2;
  ans += solve(l, m);
  ans += solve(m + 1, r);
  for (int i = l; i <= m; ++i) l_max[i] = p[i];
  for (int i = r; i > m; --i) r_max[i] = p[i];
  for (int i = m - 1; i >= l; --i) l_max[i] = std::max(l_max[i], l_max[i + 1]);
  for (int i = m + 2; i <= r; ++i) r_max[i] = std::max(r_max[i], r_max[i - 1]);
  for (int a = l; a <= m; ++a) {
    if (l_max[a] - p[a] < 0) continue;
    int b = ind_of[l_max[a] - p[a]];
    if (b > m && b <= r && r_max[b] <= l_max[a]) ++ans;
  }
  for (int b = m + 1; b <= r; ++b) {
    if (r_max[b] - p[b] < 0) continue;
    int a = ind_of[r_max[b] - p[b]];
    if (a >= l && a <= m && l_max[a] <= r_max[b]) ++ans;
  }
  return ans;
}
int main() {
  cin >> n;
  ind_of[0] = -1;
  for (int i = 0; i < n; ++i) {
    scanf("%d", p + i);
    ind_of[p[i]] = i;
  }
  cout << solve(0, n - 1) << endl;
  char I;
  cin >> I;
  return 0;
}
