#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 9;
int n, ans, a[N], b[N], l[N], r[N];
int main() {
  scanf("%d", &n);
  a[0] = a[n + 1] = N;
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &a[i]);
    b[a[i]] = i;
    for (l[i] = i - 1; a[l[i]] < a[i];) l[i] = l[l[i]];
  }
  for (int i = n; i; --i) {
    for (r[i] = i + 1; a[r[i]] < a[i];) r[i] = r[r[i]];
    int s1 = l[i], t1 = i, s2 = i, t2 = r[i];
    if (t1 - s1 > t2 - s2) swap(s1, s2), swap(t1, t2);
    for (int j = s1 + 1; j < t1; ++j)
      if (s2 < b[a[i] - a[j]] && b[a[i] - a[j]] < t2) ++ans;
  }
  printf("%d", ans);
}
