#include <bits/stdc++.h>
using namespace std;
int n;
const int maxn = 2e5 + 5;
int p[maxn];
int inv[maxn];
int l[maxn], r[maxn];
int st[maxn], tot;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &p[i]);
    inv[p[i]] = i;
  }
  tot = 0;
  for (int i = 1; i <= n; i++) {
    while (tot > 0 && p[st[tot]] <= p[i]) tot--;
    if (tot == 0)
      l[i] = 1;
    else
      l[i] = st[tot] + 1;
    st[++tot] = i;
  }
  tot = 0;
  for (int i = n; i >= 1; i--) {
    while (tot > 0 && p[st[tot]] <= p[i]) tot--;
    if (tot == 0)
      r[i] = n;
    else
      r[i] = st[tot] - 1;
    st[++tot] = i;
  }
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    if (i - l[i] < r[i] - i) {
      for (int j = l[i]; j < i; j++) {
        int val = p[i] - p[j];
        if (inv[val] > i && inv[val] <= r[i]) {
          ans++;
        }
      }
    } else {
      for (int j = i + 1; j <= r[i]; j++) {
        int val = p[i] - p[j];
        if (inv[val] >= l[i] && inv[val] < i) {
          ans++;
        }
      }
    }
  }
  cout << ans << endl;
  return 0;
}
