#include <bits/stdc++.h>

using namespace std;

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

const int N = 1.2e5 + 1;
int n, punct_initial, cur, poznoua, ver[N];
double x[N], y[N], ma, unghi, last;
vector<int> ans;
bool misca = 1;

int main(){
    f >> n;
    for(int i = 1; i <= n; i++)
        f >> x[i] >> y[i];

    f.close();
    x[0] = y[0] = 1e9;
    for(int i = 1; i <= n; i++){
        if(x[i] < x[punct_initial])
            punct_initial = i;
    }

    cur = punct_initial;
    while(misca || punct_initial != cur){
        misca = 0; // doar la inceput si sfarsit (nu il vom include a doua oara in vector) vom trece prin punctul initial
        ans.push_back(cur);
        ma = 10000;
        poznoua = cur; // poznoua = urm. punct
        for(int i = 1; i <= n; i++){
            if(ver[i] || i == cur) // nu ne intereseaza puncte deja vizitate (verificam si i == cur pentru prima iteratie)
                continue;

            unghi = atan2(x[i] - x[cur], y[i] - y[cur]);
            //cout << i << ' ' << cur << " ----- " << last / M_PI * 180 << "  ";
            if(unghi < 0)
                unghi += 2 * M_PI;

            //cout << unghi / M_PI * 180 << "  ";
            unghi -= last;
            if(unghi < 0)
                unghi += 2 * M_PI;

            //cout << unghi / M_PI * 180 << '\n';
            if(ma > unghi)
                ma = unghi, poznoua = i;
        }

        last = atan2(x[poznoua] - x[cur], y[poznoua] - y[cur]);
        if(last < 0)
            last += 2 * M_PI;

        cur = poznoua;
        ver[cur] = 1;
    }

    reverse(ans.begin(), ans.end());
    g << ans.size() << '\n';
    for(int i: ans)
        g << x[i] << ' ' << y[i] << '\n';

    g.close();
}