#include <bits/stdc++.h>
using namespace std;
const long long mk = 200005;
const long long logn = 29;
const long long mod = 1e9 + 7;
set<int> T[4 * mk];
int mx[4 * mk], n;
int ans = 0, a[mk];
int Node[4 * mk];
int init() {
  cin >> n;
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; i++) {
    if (a[i] < a[i + 1] || a[i] < a[i - 1]) continue;
    set<int> cur;
    for (int j = i - 1; a[j] < a[i] && j >= 1; j--) cur.insert(a[j]);
    for (int j = i + 1; a[j] < a[i] && j <= n; j++)
      if (cur.count(a[i] - a[j])) ans++;
  }
  return ans;
}
signed main() { cout << init(); }
