#include <bits/stdc++.h>
#define rep(i,x,n) for(int i=x; i<n; i++)
using namespace std;
struct pii {
int x, y;
bool operator<(const pii b) const { return y<b.y || (y==b.y && x<b.x); }
pii operator-(const pii b) const { return {x-b.x, y-b.y}; }
};
long cross(pii a, pii b) { return a.x*long(b.y)-a.y*long(b.x); }
long ccw(pii o, pii a, pii b) { return cross(o-a, o-b); }
int main() {
ios_base::sync_with_stdio(false);cin.tie(nullptr);
int N;
cin>>N;
vector<pii> A(N);
for(auto&[x,y]:A) cin>>x>>y;
swap(A[0], *min_element(begin(A), end(A)));
sort(begin(A)+1, end(A), [&](pii x, pii y) { return ccw(A[0], x, y)<0; });
vector<pii> D1(N), D2(N);
int a=0, c=0;
rep(i, 1, N) D2[i]={2, 0};
rep(i, 0, N) {
rep(j, 0, i) {
if(ccw(A[0], A[j], A[i])==0) continue;
#define maxi(a, b, c) if(a.x<b.x+1) a={b.x+1, c}
if(ccw(A[D2[j].y], A[j], A[i])<0) maxi(D1[i], D2[j], j);
if(ccw(A[D1[j].y], A[j], A[i])>0) maxi(D2[i], D1[j], j);
}
if(D2[a].x<D2[i].x) a=i;
}
if(D2[a].x<4) {
cout<<"0\n";
return 0;
}
cout<<D2[a].x<<'\n'<<A[0].x<<' '<<A[0].y<<'\n';
do cout<<A[a].x<<' '<<A[a].y<<'\n'; while(a=c++%2 ? D1[a].y : D2[a].y);
}
