#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0;
  char ch = getchar();
  while (!isdigit(ch)) ch = getchar();
  while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
  return x;
}
int a[200010], pos[200010], L[200010], R[200010], s[200010];
int main() {
  int n = read(), top = 0, ans = 0;
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]), pos[a[i]] = i;
  for (int i = 1; i <= n; i++) {
    while (top && a[s[top]] < a[i]) top--;
    L[i] = s[top], s[++top] = i;
  }
  s[top = 0] = n + 1;
  for (int i = n; i >= 1; i--) {
    while (top && a[s[top]] < a[i]) top--;
    R[i] = s[top], s[++top] = i;
  }
  for (int i = 1; i <= n; i++) {
    if (i - L[i] < R[i] - i) {
      for (int j = L[i] + 1; j < i; j++)
        if (pos[a[i] - a[j]] > i && pos[a[i] - a[j]] < R[i]) ans++;
    } else {
      for (int j = i + 1; j < R[i]; j++)
        if (pos[a[i] - a[j]] < i && pos[a[i] - a[j]] > L[i]) ans++;
    }
  }
  cout << ans << endl;
  return 0;
}
