#include <bits/stdc++.h>
using namespace std;
int a[200005], l[200005], r[200005], s[200005], cnt, s2[200005], b[200005],
    pos[200005];
int main(int argc, char** argv) {
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    pos[a[i]] = i;
  }
  for (int i = 1; i <= n; i++) {
    while (cnt && s[cnt] < a[i]) --cnt;
    l[i] = s2[cnt];
    s[++cnt] = a[i];
    s2[cnt] = i;
  }
  cnt = 0;
  for (int i = n; i >= 1; i--) {
    while (cnt && s[cnt] < a[i]) --cnt;
    r[i] = s2[cnt];
    s[++cnt] = a[i];
    s2[cnt] = i;
    if (!r[i]) r[i] = n + 1;
    ++l[i], --r[i];
  }
  long long ans = 0;
  for (int i = 1; i <= n; i++) {
    if (i - l[i] < r[i] - i) {
      for (int j = i; j >= l[i]; j--)
        ans += (pos[a[i] - a[j]] <= r[i] && pos[a[i] - a[j]] > i);
    } else {
      for (int j = r[i]; j >= i; j--)
        ans += (pos[a[i] - a[j]] <= i && pos[a[i] - a[j]] >= l[i]);
    }
  }
  cout << ans;
  return 0;
}
