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 int N = 400003;
int n, a[N], p[N], st[19][N], lg2[N], ans;
inline int ask(int l, int r) {
  int k = lg2[r - l + 1];
  return max(st[k][l], st[k][r - (1 << k) + 1]);
}
inline void dfs(int l, int r) {
  if (l >= r) return;
  int mid = p[ask(l, r)];
  if (mid < (l + r >> 1)) {
    for (register int i = l; i < mid; i++)
      if (p[a[mid] - a[i]] > mid && p[a[mid] - a[i]] <= r) ++ans;
  } else {
    for (register int i = mid + 1; i <= r; i++)
      if (p[a[mid] - a[i]] < mid && p[a[mid] - a[i]] >= l) ++ans;
  }
  dfs(l, mid - 1);
  dfs(mid + 1, r);
}
int main() {
  scanf("%d", &n);
  for (register int i = 1; i <= n; i++) {
    scanf("%d", a + i);
    p[a[i]] = i;
    st[0][i] = a[i];
  }
  for (register int i = 1; i <= 18; i++)
    for (register int j = 1; j <= n - (1 << i - 1) + 1; j++)
      st[i][j] = max(st[i - 1][j], st[i - 1][j + (1 << i - 1)]);
  lg2[0] = -1;
  for (register int i = 1; i <= n; i++) lg2[i] = lg2[i >> 1] + 1;
  lg2[0] = 0;
  dfs(1, n);
  printf("%d", ans);
}
