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;
namespace shyutsuryoku {
const int STRSZ = 3e5 + 13;
char inbufer[STRSZ];
inline void cscan(string& i) {
  int c = getc(stdin), cnt = 0;
  while (c <= 32) c = getc(stdin);
  while (c > 32) *(inbufer + cnt) = c, c = getc(stdin), ++cnt;
  *(cnt + inbufer) = 0;
  i = inbufer;
}
inline void cprint(string& i) {
  char* second = new char[i.size() + 1];
  strcpy(second, i.c_str());
  while (*second) putchar(*second), second++;
}
inline void cprint(const char*& i) {
  int cnt = 0;
  while (*(i + cnt)) putc(*(i + cnt), stdout), cnt++;
}
inline void cscan(int& i) {
  i = 0;
  int c = getc(stdin), b = 0;
  while (c <= 32) c = getc(stdin);
  if (c == '-') b = 1, c = getc(stdin);
  while (c >= '0' && c <= '9') i *= 10, i += c - '0', c = getc(stdin);
  if (b) i = -i;
}
inline void cprint(int i) {
  if (i < 0) putc('-', stdout), i = -i;
  int sz = 0;
  char ans[12];
  while (i || !sz) ans[sz++] = i % 10 + '0', i /= 10;
  while (sz--) putc(ans[sz], stdout);
}
inline void cscan(long long& i) {
  i = 0;
  int c = getc(stdin), b = 1;
  while (c <= 32) c = getc(stdin);
  if (c == '-') b = -1, c = getc(stdin);
  while (c >= '0' && c <= '9') i *= 10, i += c - '0', c = getc(stdin);
  i *= b;
}
inline void cprint(long long i) {
  if (i < 0) putc('-', stdout), i = -i;
  int sz = 0;
  char ans[21];
  while (i || !sz) ans[sz++] = i % 10 + '0', i /= 10;
  while (sz--) putc(ans[sz], stdout);
}
inline void cscan(unsigned& i) {
  i = 0;
  int c = getc(stdin);
  while (c <= 32) c = getc(stdin);
  while (c >= '0' && c <= '9') i *= 10, i += c - '0', c = getc(stdin);
}
inline void cprint(unsigned i) {
  int sz = 0;
  char ans[12];
  while (i || !sz) ans[sz++] = i % 10 + '0', i /= 10;
  while (sz--) putc(ans[sz], stdout);
}
inline void cscan(unsigned long long& i) {
  i = 0;
  int c = getc(stdin);
  while (c <= 32) c = getc(stdin);
  while (c >= '0' && c <= '9') i *= 10, i += c - '0', c = getc(stdin);
}
inline void cprint(unsigned long long i) {
  int sz = 0;
  char ans[21];
  while (i || !sz) ans[sz++] = i % 10 + '0', i /= 10;
  while (sz--) putc(ans[sz], stdout);
}
inline void cscan(double& i) { scanf("%lf", &i); }
inline void cprint(double i) { printf("%lf", i); }
inline void cprint(char i) { putc(i, stdout); }
inline void cscan(char& i) {
  int b = getc(stdin);
  while (b <= 32) b = getc(stdin);
  i = b;
}
template <class T>
inline void cscan(pair<T, T>& i) {
  cscan(i.first);
  cscan(i.second);
}
template <class T>
inline void cscan(vector<T>& i) {
  for (auto& j : i) cscan(j);
}
template <class T>
inline void cprint(vector<T>& i) {
  for (auto& j : i) cprint(j), cprint(' ');
}
template <class T>
inline void cprint(vector<vector<T> >& i) {
  for (auto& j : i) cprint(j), cprint('\n');
}
template <class T>
ostream& operator,(ostream& os, T v) {
  cprint(v);
  return os;
}
template <class T>
istream& operator,(istream& is, T& v) {
  cscan(v);
  return is;
}
}  // namespace shyutsuryoku
using namespace shyutsuryoku;
void AnimeConservativeRevolution();
int main() {
  srand(time(0));
  AnimeConservativeRevolution();
  return 0;
}
void AnimeConservativeRevolution() {
  int n, ans = 0;
  cin, n;
  vector<int> in(n), loc(n + 1);
  cin, in;
  for (int i = 0; i < n; i++) loc[in[i]] = i;
  set<int> grn;
  grn.insert(-1);
  grn.insert(n);
  for (int i = n; i >= 1; i--) {
    auto it = grn.lower_bound(loc[i]);
    int r = *it;
    it--;
    int l = *it, sr = loc[i];
    if (sr - l < r - sr) {
      for (int j = l + 1; j < sr; j++) {
        if (loc[i - in[j]] > sr && loc[i - in[j]] < r) ans++;
      }
    } else {
      for (int j = r - 1; j > sr; j--) {
        if (loc[i - in[j]] > l && loc[i - in[j]] < sr) ans++;
      }
    }
    grn.insert(loc[i]);
  }
  cout, ans;
}
