You are given a permutation p of n integers 1, 2, ..., n (a permutation is an array where each element from 1 to n occurs exactly once).

Let's call some subsegment p[l, r] of this permutation special if p_l + p_r = max _{i = l}^{r} p_i. Please calculate the number of special subsegments.

Input

The first line contains one integer n (3 ≤ n ≤ 2 ⋅ 10^5).

The second line contains n integers p_1, p_2, ..., p_n (1 ≤ p_i ≤ n). All these integers are pairwise distinct.

Output

Print the number of special subsegments of the given permutation.

Examples

Input


5
3 4 1 5 2


Output


2


Input


3
1 3 2


Output


1

Note

Special subsegments in the first example are [1, 5] and [1, 3].

The only special subsegment in the second example is [1, 3].
#include <bits/stdc++.h>
using namespace std;
const long long llINF = 9223372036854775807;
const int INF = 2147483647;
const int maxn = 2e5 + 7;
const int maxm = 5e4 + 7;
const long long mod = 1e9 + 7;
const double pi = acos(-1.0);
const double eps = 1e-12;
int n;
int a[maxn];
int p[maxn];
set<int> s;
int ans;
int main(int argc, char const *argv[]) {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    p[a[i]] = i;
  }
  s.insert(0);
  s.insert(n + 1);
  for (int i = n; i >= 1; i--) {
    set<int>::iterator p1 = --s.lower_bound(p[i]);
    set<int>::iterator p2 = s.upper_bound(p[i]);
    if (*p2 - p[i] > p[i] - *p1) {
      for (int j = *p1 + 1; j < p[i]; j++)
        if (p[i - a[j]] > p[i] && p[i - a[j]] < *p2) ans++;
    } else {
      for (int j = p[i] + 1; j < *p2; j++)
        if (p[i - a[j]] < p[i] && p[i - a[j]] > *p1) ans++;
    }
    s.insert(p[i]);
  }
  printf("%d\n", ans);
  return 0;
}
