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>
const int M = 2e5 + 5;
int n, ans, a[M], L[M], R[M], pos[M];
int top, stk[M];
signed main() {
  register int i, j;
  scanf("%d", &n);
  for (i = 1; i <= n; ++i) scanf("%d", a + i), pos[a[i]] = i;
  for (i = 1; i <= n; ++i) {
    while (top && a[i] > a[stk[top]]) --top;
    L[i] = stk[top] + 1;
    stk[++top] = i;
  }
  top = 0;
  for (i = n; i >= 1; --i) {
    while (top && a[i] > a[stk[top]]) --top;
    R[i] = stk[top] - 1;
    stk[++top] = i;
  }
  for (i = 1; i <= n; ++i) {
    if (!L[i]) L[i] = 1;
    if (!~R[i]) R[i] = n;
  }
  for (i = 1; i <= n; ++i) {
    if (i - L[i] >= R[i] - i) {
      for (j = i + 1; j <= R[i]; ++j)
        ans += L[i] <= pos[a[i] - a[j]] && pos[a[i] - a[j]] <= i;
    } else {
      for (j = L[i]; j <= i - 1; ++j)
        ans += i <= pos[a[i] - a[j]] && pos[a[i] - a[j]] <= R[i];
    }
  }
  printf("%d", ans);
}
