#include <bits/stdc++.h>
#define eb emplace_back
#define fi first
#define se second
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
ll operator * (const pll &a, const pll &b) { return a.fi * b.se - b.fi * a.se; }
ll ccw(const pll &a, const pll &b, const pll &c) { return a*b + b*c + c*a; }
ll MP[3005][3005];
inline ll ccw(int a, int b, int c) { return MP[a][b] + MP[b][c] - MP[a][c]; }
int D[3005][3005], RD[3005][3005];
int E[3005][3005], RE[3005][3005];
int NV[3005], NVn;
int PV[3005], PVn;
pll P[3005];
int N;
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
cin >> N;
for(int i = 0; i < N; i++) {
cin >> P[i].fi >> P[i].se;
if(P[i].se < P[0].se) swap(P[0], P[i]);
}
N--;
sort(P+1, P+N+1, [&](const pll &a, const pll &b) { return ccw(P[0], a, b) > 0; });
for(int i = 1; i <= N; i++) for(int j = 0; j < i; j++) {
MP[i][j] = P[i] * P[j];
MP[j][i] = -MP[i][j];
}
for(int i = 1; i <= N; i++) {
D[i][0] = 2;
NVn = PVn = 0;
{
int k = i+1;
for(; k <= N && !ccw(0, i, k); k++);
for(; k <= N; k++) NV[NVn++] = k;
}
{
PV[PVn++] = 0;
int j = i-1;
for(; j && !ccw(0, i, j); j--);
for(; j; j--) PV[PVn++] = j;
}
sort(NV, NV+NVn, [&](int a, int b) { return ccw(i, a, b) > 0; });
sort(PV, PV+PVn, [&](int a, int b) { return ccw(i, a, b) > 0; });
for(int ki = 0, k, ji = 0, j, mx = 0, mxj; ki < NVn; ki++) {
k = NV[ki];
for(; ji < PVn; ji++) {
j = PV[ji];
if(ccw(j, i, k) <= 0) break;
if(mx < D[i][j]) {
mx = D[i][j];
mxj = j;
}
}
if(mx) {
E[k][i] = mx + 1;
RE[k][i] = mxj;
}
}
for(int ki = NVn-1, k, ji = PVn-1, j, mx = 0, mxj; 0 <= ki; ki--) {
k = NV[ki];
for(; 0 <= ji; ji--) {
j = PV[ji];
if(ccw(j, i, k) >= 0) break;
if(mx < E[i][j]) {
mx = E[i][j];
mxj = j;
}
}
if(mx) {
D[k][i] = mx + 1;
RD[k][i] = mxj;
}
}
}
{
int Ans = 0, I, J;
for(int i = N; i; i--) for(int j = i-1; j; j--)
if(Ans < D[i][j]) {
Ans = D[i][j];
I = i; J = j;
}
if(Ans < 4) { puts("0"); exit(0); }
cout << Ans << '\n';
vector<int> V;
for(int t = 0; 2 < Ans; Ans--, t ^= 1) {
V.eb(I);
I = (t ? RE : RD)[I][J];
swap(I, J);
}
V.eb(I); V.eb(J);
reverse(V.begin(), V.end());
for(int v : V) cout << P[v].fi << ' ' << P[v].se << '\n';
}
return 0;
}
