#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <algorithm>
using namespace std;

ifstream f("infasuratoare.in");
ofstream g("infasuratoare.out");

class Punct;
double prodVectorial(const Punct&, const Punct&, const Punct&);
vector<Punct> v, stck;

class Punct{
public:
    double x, y;
    Punct(double x, double y):x(x), y(y){};
    friend bool operator<(const Punct& a, const Punct& b){
        return prodVectorial(v[0], a, b) > 0;
    }
};



double prodVectorial(const Punct &a, const Punct &b, const Punct &c){
    return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
//    return a.x * b.y + b.x * c.y + c.x * a.y -
//           b.y * c.x + c.y * a.x + a.y * b.x;
}

void infasuratoare(){
    stck.push_back(v[0]);
    stck.push_back(v[1]);

    for(int i = 2; i < v.size(); ++i){
        while(stck.size() > 1 && prodVectorial(stck[stck.size() - 2], stck.back(), v[i]) < 0)
            stck.pop_back();
        stck.push_back(v[i]);

    }


}


int main()
{
    int n;
    double x, y;
    f>>n;
    while(n--){
        f>>x>>y;
        Punct p(x, y);
        v.push_back(p);
    }

    int mnx = v[0].x, mny = v[0].y;

    for(int i = 1; i < v.size(); ++i){
        if(v[i].x < mnx)
            mnx = v[i].x, mny = v[i].y, swap(v[0], v[i]);
        else
            if(v[i].x == mnx && v[i].y < mny)
                mnx = v[i].x, mny = v[i].y, swap(v[0], v[i]);

    }
    sort(v.begin()+1, v.end());

    infasuratoare();

//
//    for(int i = 0; i < v.size(); ++i)
//        cout<<setprecision(9)<<v[i].x<<' '<<v[i].y<<'\n';

    for(int i = 0; i < stck.size(); ++i)
        g<<setprecision(9)<<stck[i].x<<' '<<stck[i].y<<'\n';


    return 0;
}