#include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int n;     cin >> n;     vector<int> arr(n), lefts(n), rights(n);     for (int &x : arr) cin >> x;     stack<int> positions;     for (int i = 0; i < n; ++i) {       while (!positions.empty() && arr[positions.top()] <= arr[i])         positions.pop();       if (positions.empty()) {         lefts[i] = -1;       } else {         lefts[i] = positions.top();       }       positions.push(i);     }     while (!positions.empty()) positions.pop();     for (int i = n - 1; i >= 0; --i) {       while (!positions.empty() && arr[positions.top()] <= arr[i])         positions.pop();       if (positions.empty()) {         rights[i] = n;       } else {         rights[i] = positions.top();       }       positions.push(i);     }     while (!positions.empty()) positions.pop();     vector<int> inv(n);     for (int i = 0; i < n; ++i) {       inv[arr[i]] = i;     }     long long res = 0;     for (int i = 0; i < n; ++i) {       int distL = i - lefts[i];       int distR = rights[i] - i;       if (distL < distR) {         for (int j = lefts[i] + 1; j < i; ++j) {           if (arr[j] > arr[i]) continue;           int Right = arr[i] - arr[j];           int pos = inv[Right];           if (pos > i && pos < rights[i]) {             ++res;           }         }       } else {         for (int j = i + 1; j < rights[i]; ++j) {           if (arr[j] > arr[i]) continue;           int Left = arr[i] - arr[j];           int pos = inv[Left];           if (pos < i && pos > lefts[i]) {             ++res;           }         }       }     }     cout << res << endl;     return 0;   }   