func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAX = 10000;   int n;   set<pair<int, int> > a;   set<pair<int, int> >::iterator it;   pair<int, int> b[MAX];   void dive(int s, int e) {     if (e - s == 1) return;     int mid = s + e;     mid /= 2;     dive(s, mid);     dive(mid, e);     for (int i = s; i < e; i++) a.insert(make_pair(b[mid].first, b[i].second));   }   int main() {     cin >> n;     int x, y;     for (int i = 0; i < n; i++) {       cin >> b[i].first >> b[i].second;       a.insert(b[i]);     }     sort(b, b + n);     dive(0, n);     cout << a.size() << endl;     for (it = a.begin(); it != a.end(); it++)       cout << it->first <<     << it->second << endl;     return 0;   }   