// #pragma GCC optimize("Ofast")
// #pragma GCC target("avx,avx2,fma,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define emb emplace_back
#define pb push_back
#define mt make_tuple
#define fi first
#define se second
#define uniq(x) (x).erase(unique(all(x)), x.end())
#define BIT(x, i) (((x)>>(i))&1)
#define MASK(i) (1LL<<(i))
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<long long> vl;
template<typename T1, typename T2> bool mini(T1 &a, T2 b)
{if(a>b) a=b; else return 0; return 1;}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b)
{if(a<b) a=b; else return 0; return 1;}
const int mxN = 3e3 + 7;
const int md = 1e9 + 7;
const int inf = 1e9 + 7;
int dp[mxN][mxN][2];
pii trace[mxN][mxN][2];
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int n;
cin >> n;
vector<pii> a(n + 7);
for (int i = 1; i <= n; i++) {
cin >> a[i].fi >> a[i].se;
if (i > 1 && a[1].se > a[i].se) {
swap(a[1], a[i]);
}
}
auto cross = [&](pii a, pii b) {
return 1LL * a.fi * b.se - 1LL * a.se * b.fi;
};
auto cross3 = [&](pii a, pii b, pii c) {
pii t1 = make_pair(b.fi - a.fi, b.se - a.se);
pii t2 = make_pair(c.fi - a.fi, c.se - a.se);
return cross(t1, t2);
};
auto sq = [&](pii a, pii b) {
return 1LL * (a.fi - b.fi) * (a.fi - b.fi) + 1LL * (a.se - b.se) * (a.se - b.se);
};
sort (a.begin() + 2, a.begin() + 1 + n, [&](pii x, pii y){
ll temp = cross3(a[1], x, y);
if (temp != 0) return temp > 0;
return sq(a[1], x) < sq(a[1], y);
});
// for (int i = 1; i <= n; i++) cout << a[i].fi << ' ' << a[i].se << '\n';
memset(dp, -0x3f, sizeof(dp));
int res = dp[0][0][0];
array<int, 3> path;
for (int i = 2; i <= n; i++) {
for (int j = 1; j < i; j++) {
for (int cur = 0; cur < 2; cur++) {
if (j == 1) {
if (cur == 0) dp[i][j][cur] = 2;
} else {
for (int k = 1; k < j; k++) {
if (cur == 1) {
if (cross3(a[k], a[j], a[i]) > 0) {
if (maxi(dp[i][j][cur], dp[j][k][cur ^ 1] + 1)) {
trace[i][j][cur] = {j, k};
}
}
} else {
if (cross3(a[k], a[j], a[i]) < 0) {
if (maxi(dp[i][j][cur], dp[j][k][cur ^ 1] + 1)) {
trace[i][j][cur] = {j, k};
}
}
}
}
}
if (cur == 0 && maxi(res, dp[i][j][cur])) {
path = {i, j, cur};
}
}
}
}
vector<int> ans;
ans.pb(path[0]);
ans.pb(path[1]);
while (path[0] != 0 && path[1] != 0) {
pii temp = trace[path[0]][path[1]][path[2]];
path[0] = temp.fi;
path[1] = temp.se;
path[2] ^= 1;
if (path[1] > 0) ans.pb(path[1]);
}
reverse(all(ans));
if (sz(ans) < 4) {
cout << 0 << '\n';
return 0;
}
cout << sz(ans) << '\n';
for (auto it : ans) cout << a[it].fi << ' ' << a[it].se << '\n';
return 0;
}
