func_code_string: #include <bits/stdc++.h>   using namespace std;   bool binary(vector<int> v, int key) {     int lo = 0, hi = v.size() - 1;     while (lo <= hi) {       int mid = (lo + hi) / 2;       if (v[mid] == key)         return true;       else if (v[mid] < key)         lo = mid + 1;       else         hi = mid - 1;     }     return false;   }   int main() {     int n, ans = 0, l = 0, r = 0, u = 0, d = 0;     cin >> n;     vector<pair<int, int>> v;     for (int i = 0; i < n; i++) {       int t1, t2;       cin >> t1 >> t2;       v.push_back(make_pair(t1, t2));     }     for (int i = 0; i < n; i++) {       for (int j = 0; j < n; j++) {         if (v[j].first == v[i].first && v[j].second < v[i].second) d++;         if (v[j].first == v[i].first && v[j].second > v[i].second) u++;         if (v[j].first < v[i].first && v[j].second == v[i].second) l++;         if (v[j].first > v[i].first && v[j].second == v[i].second) r++;       }       if (d && r && l && u) ans++;       d = 0, r = 0, l = 0, u = 0;     }     cout << ans;     return 0;   }   