#include<iostream> #include<map> #include<stdio.h> #include<algorithm> using namespace std; int main() { long long N; while (cin>>N) { //cin >> N; map<long long, long long> X; for (size_t i = 0; i < N; i++) { long long x, y; cin >> x >> y; X.insert(make_pair(x, y)); } long long max_x = 0; long long max_y = 0; map<long long, long long> maptest; map<long long, long long>::iterator ittest; map<long long, long long>::iterator it; for (it = X.begin(), ittest = X.begin();it != X.end();++it) { maptest.insert(make_pair(it->first, it->second)); if (maptest.size() > 1) { if ((it->first > max_x) && (it->second > max_y)) { maptest.erase(max_x); //it++; } } max_x = it->first; max_y = it->second; } for (it = maptest.begin();it != maptest.end();++it) { cout << it->first << " " << it->second << endl; } } return 0; }