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>
const double esp = 1e-6;
const double pi = acos(-1.0);
const int INF = 0x3f3f3f3f;
const int inf = 1e9;
using namespace std;
int read() {
  char ch = getchar();
  int x = 0, f = 1;
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
const int N = 2e5 + 5;
int n;
int dp[N][30];
int a[N], pos[N];
int ans;
void init() {
  for (int i = 1; i <= n; i++) {
    dp[i][0] = a[i];
  }
  for (int j = 1; (1 << j) <= n; j++) {
    for (int i = 1; i + (1 << j) - 1 <= n; i++) {
      dp[i][j] = max(dp[i][j - 1], dp[i + (1 << (j - 1))][j - 1]);
    }
  }
}
int querry(int l, int r) {
  int k = 0;
  while ((1 << (k + 1)) <= (r - l + 1)) {
    k++;
  }
  return max(dp[l][k], dp[r - (1 << k) + 1][k]);
}
void merge(int l, int r) {
  if (l + 1 >= r) return;
  int mx = querry(l, r);
  int mid = pos[mx];
  merge(l, mid - 1);
  merge(mid + 1, r);
  int lf = mid - l;
  int rt = r - mid;
  if (lf > rt) {
    for (int i = mid + 1; i <= r; i++) {
      int temp = pos[mx - a[i]];
      if (temp >= l && temp < mid) ans++;
    }
  } else {
    for (int i = l; i <= mid - 1; i++) {
      int temp = pos[mx - a[i]];
      if (temp <= r && temp > mid) ans++;
    }
  }
}
int main() {
  n = read();
  for (int i = 1; i <= n; i++) {
    a[i] = read();
    pos[a[i]] = i;
  }
  init();
  merge(1, n);
  cout << ans;
  return 0;
}
