#include <bits/stdc++.h>
using namespace std;
using LL = long long;
const LL MOD = (LL)1e9 + 7;
const LL NS = (LL)3004;
LL N;
pair<LL, LL> a[NS];
pair<LL, LL> mid[NS][NS];
LL dp[NS], from[NS];
inline LL ccw(pair<LL, LL> A, pair<LL, LL> B, pair<LL, LL> C){
B.first -= A.first, C.first -= A.first;
B.second -= A.second, C.second -= A.second;
LL val = B.first * C.second - B.second * C.first;
if(val > 0) return 1;
if(val < 0) return -1;
return 0;
}
void out(LL x){
if(x == 1){
cout << a[x].first << ' ' << a[x].second << '\n';
return;
}
out(from[x]);
if(from[x] != 1){
cout << mid[from[x]][x].first << ' ' << mid[from[x]][x].second << '\n';
}
cout << a[x].first << ' ' << a[x].second << '\n';
}
int main(){
// freopen("input.txt", "r", stdin);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> N;
LL low = MOD, pos;
for(LL i = 1; i <= N; ++i){
cin >> a[i].first >> a[i].second;
if(a[i].second < low){
low = a[i].second;
pos = i;
}
}
swap(a[1], a[pos]);
sort(a + 2, a + N + 1, [&](pair<LL, LL> A, pair<LL, LL> B){return ccw(a[1], A, B) > 0;});
for(LL i = 2; i <= N; ++i){
LL x = i + 1;
pair<LL, LL> pos = {MOD, MOD};
for(LL j = i + 2; j <= N; ++j){
while(x <= N && ccw(a[1], a[x], a[i]) == 0){
++x;
}
while(x < j && ccw(a[1], a[x], a[j]) > 0){
if(pos.first == MOD){
pos = a[x];
}
else if(ccw(a[i], pos, a[x]) > 0){
pos = a[x];
}
++x;
}
mid[i][j] = {MOD, MOD};
if(pos.first != MOD && ccw(a[i], pos, a[j]) < 0){
mid[i][j] = pos;
}
}
}
LL mx = 0, num;
for(LL i = 2; i <= N; ++i){
if(!dp[i]){
dp[i] = 2;
from[i] = 1;
}
for(LL j = i + 2; j <= N; ++j){
if(mid[i][j].first != MOD){
if(dp[i] + 2 > dp[j]){
dp[j] = dp[i] + 2;
from[j] = i;
}
}
}
if(dp[i] > mx){
mx = dp[i];
num = i;
}
}
if(mx == 2){
cout << 0;
return 0;
}
cout << mx << '\n';
out(num);
return 0;
}
