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 readInt() {
  int x;
  if (scanf(" %d", &x) != EOF) return x;
  return -1;
}
long long int readLint() {
  long long int x;
  if (cin >> x) return x;
  return -1;
}
string readString() {
  string s;
  if (cin >> s) return s;
  return "";
}
struct SingleCase {
  vector<int> getRightBoundary(vector<int>& v) {
    int n = v.size();
    vector<int> right(n, n);
    vector<int> q;
    for (int i = 0; i < n; ++i) {
      while (true) {
        if (q.empty() || v[i] < v[q.back()]) {
          q.push_back(i);
          break;
        } else {
          right[q.back()] = i;
          q.erase(q.end() - 1);
        }
      }
    }
    return right;
  }
  vector<int> getLeftBoundary(vector<int>& v) {
    int n = v.size();
    vector<int> left(n, -1);
    vector<int> q;
    for (int i = n - 1; i >= 0; i--) {
      while (true) {
        if (q.empty() || v[i] < v[q.back()]) {
          q.push_back(i);
          break;
        } else {
          left[q.back()] = i;
          q.erase(q.end() - 1);
        }
      }
    }
    return left;
  }
  bool solveCase() {
    int n = readInt();
    if (n < 0) return false;
    vector<int> v;
    for (int i = 0; i < n; ++i) v.push_back(readInt() - 1);
    vector<int> pos(n, -1);
    for (int i = 0; i < n; ++i) pos[v[i]] = i;
    vector<int> right = getRightBoundary(v);
    vector<int> left = getLeftBoundary(v);
    long long int ret = 0;
    for (int i = 0; i < n; ++i) {
      if (i - left[i] > right[i] - i) {
        for (int j = right[i] - 1; j > i; j--) {
          int rem = v[i] - 1 - v[j];
          assert(rem >= 0);
          if (pos[rem] > left[i] && pos[rem] < i) ret++;
        }
      } else {
        for (int j = left[i] + 1; j < i; j++) {
          int rem = v[i] - v[j] - 1;
          assert(rem >= 0);
          if (pos[rem] > i && pos[rem] < right[i]) ret++;
        }
      }
    }
    cout << ret << endl;
    return true;
  }
};
int main() {
  while (SingleCase().solveCase()) {
  }
}
