#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")
#include <bits/stdc++.h>
#include <chrono>
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define rrep(i, n) for (int i = 1; i <= n; ++i)
#define x first
#define y second
using namespace std;
typedef long long ll;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V> void __print(const pair<T, V> &x) {
cerr << '{';
__print(x.first);
cerr << ", ";
__print(x.second);
cerr << '}';
}
template <typename T> void __print(const T &x) {
int f = 0;
cerr << '{';
for (auto &i : x)
cerr << (f++ ? ", " : ""), __print(i);
cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V> void _print(T t, V... v) {
__print(t);
if (sizeof...(v))
cerr << ", ";
_print(v...);
}
#ifndef ONLINE_JUDGE
#define dbg(x...) \
cerr << "\e[91m" << __func__ << ":" << __LINE__ << " [" << #x << "] = ["; \
_print(x); \
cerr << "\e[39m" << endl;
#else
#define dbg(x...)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll randint(ll lb, ll ub) { return uniform_int_distribution<ll>(lb, ub)(rng); }
typedef pair<long long,long long> pll;
// a -> b -> c ccw?
int ccw(pair<ll,ll> a, pair<ll,ll> b, pair<ll,ll> c){
ll tmp = (b.x-a.x)*(c.y-a.y) - (b.y-a.y)*(c.x-a.x);
return (tmp>0) - (tmp<0);
}
ll dist(pll a, pll b){
return (a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y);
}
int dp[3010], dp1[3010], bitch[3010];
void solve(){
int n;
vector<pll> v;
cin >> n;
rep(i,n){
int a,b; cin >> a >> b;
v.pb({a,b});
}
sort(v.begin(),v.end(),[](auto a, auto b){
return a.y < b.y;
});
auto fuck = v[0];
sort(v.begin()+1,v.end(),[&](auto a, auto b){
int ff = ccw(fuck,a,b);
if(ff!=0) return ff<0;
return dist(a,fuck) < dist(b,fuck);
});
dbg(v)
for(int i=1; i<n; ){
int j = i;
int dpM = 0, mk = i-1;
while(j<n && ccw(fuck,v[i],v[j])==0) j++;
if(i==1){
i=j; continue;
}
for(int k=i-1; k>=1; k--){
int tt = ccw(v[j-1],v[mk],v[k]);
if(tt>0){
mk = k;
}
if(tt<0){
if(dp[k]+2>dpM){
bitch[j-1] = mk;
dpM = dp[k]+2;
dp[j-1] = dpM;
dp1[j-1] = k;
}
}
}
i=j;
}
int M = 0,midx = -1;
for(int i=1; i<n; i++){
if(dp[i]>M) M = dp[i], midx = i;
}
if(M==0){
cout << 0; return;
}
cout << M+2 << "\n";
vector<int> ans;
ans.pb(0);
int st = midx;
while(1){
if(dp[st]==0){
ans.pb(st); break;
}
ans.pb(st);
ans.pb(bitch[st]);
st = dp1[st];
}
for(auto i : ans) cout << v[i].x << " " << v[i].y << "\n";
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int t = 1;
// cin >> t;
while(t--) solve();
return 0;
}
