#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <set>
#include <array>
using namespace std;

int main() {
   
    set<pair<int, int> > st;
    st.insert({1, 2});
    
    for(auto x : st) {
        cout << x.first << " " << x.second << endl;
    }
   
    return 0;
}