#include <bits/stdc++.h>
#include "trilib.h"
#define MAXN 100007
using namespace std;
int n;
static long long *x, *y;
static int queries=0;
/*static void init() {
static int is_inited=0;
if (is_inited)
return;
is_inited=1;
assert(scanf("%d", &n)==1);
x=(long long*)malloc((n+1)*sizeof(long long));
y=(long long*)malloc((n+1)*sizeof(long long));
for (int i=1; i<=n; i++){
x[i]=rand()%100+1;
y[i]=rand()%100+1;
//cin>>x[i]>>y[i];
//assert(scanf("%lld%lld", &x[i], &y[i])==2);
}
}
int get_n() {
init();
return n;
}
int is_clockwise(int a, int b, int c) {
init();
assert(a>=1 && a<=n);
assert(b>=1 && b<=n);
assert(c>=1 && c<=n);
assert(a!=b && a!=c && b!=c);
queries++;
if(queries == 1000 * 1000 + 1)
printf("Too many queries!");
return (x[b]-x[a])*(y[c]-y[a])-(x[c]-x[a])*(y[b]-y[a])<0;
}
void give_answer(int s) {
init();
printf("%d\n", s);
}*/
int li[MAXN],tim;
bool check(int x,int y,vector<int> w){
if(x==y)return false;
for(int i:w){
if(i==x or i==y)continue;
if(is_clockwise(x,i,y))return false;
}
return true;
}
vector<int> combine(vector<int> a,vector<int> b){
if(a.empty())return b;
if(b.empty())return a;
deque<int> l,r;
vector<int> res,c;
c=a;
for(int i:b)c.push_back(i);
tim++;
int pos=0;
for(int i=0;i<a.size();i++){
if(check(a[i],a[(i+1)%a.size()],b)){
l.push_back(i);
}
}
while(!l.empty() and (l.back()+1)%a.size()==l.front()){
l.push_back(l.front());
l.pop_front();
}
tim++;
for(int i=0;i<b.size();i++){
if(check(b[i],b[(i+1)%b.size()],a)){
r.push_back(i);
}
}
while(!r.empty() and (r.back()+1)%b.size()==r.front()){
r.push_back(r.front());
r.pop_front();
}
for(int i=0;i<l.size();i++){
if(i==0){
res.push_back(a[l[i]]);
res.push_back(a[(l[i]+1)%a.size()]);
}else{
res.push_back(a[(l[i]+1)%a.size()]);
}
}
for(int i=0;i<r.size();i++){
if(i==0){
res.push_back(b[r[i]]);
res.push_back(b[(r[i]+1)%b.size()]);
}else{
res.push_back(b[(r[i]+1)%b.size()]);
}
}
for(int i=0;i<l.size();i++)l[i]=a[l[i]];
for(int i=0;i<r.size();i++)r[i]=b[r[i]];
if(l.empty()){
for(int i:a){
if(check(i,res.front(),c) and check(res.back(),i,c)){
res.push_back(i); break;
}
}
return res;
}
if(r.empty()){
for(int i:b){
if(check(i,res.front(),c) and check(res.back(),i,c)){
res.push_back(i); break;
}
}
return res;
}
if(res.size()>2 and !is_clockwise(res[0],res[1],res[2]))reverse(res.begin(),res.end());
return res;
}
vector<int> solve(vector<int> w){
if(w.size()<=2)return w;
if(w.size()==3){
if(!is_clockwise(w[0],w[1],w[2])){
swap(w[0],w[2]);
}
return w;
}
vector<int> sol;
int r1=rand()%int(w.size());
int r2=r1;
while(r2==r1){
r2=rand()%int(w.size());
}
vector<int> l,r;
for(int i=0;i<w.size();i++){
if(i==r1 or i==r2)continue;
if(is_clockwise(w[r1],w[i],w[r2]))l.push_back(w[i]);
else r.push_back(w[i]);
}
vector<int> convL=solve(l);
vector<int> convR=solve(r);
sol=combine(convL,{w[r1],w[r2]});
sol=combine(sol,convR);
return sol;
}
vector<int> perm;
int main(){
n=get_n();
for(int i=1;i<=n;i++){
perm.push_back(i);
}
vector<int> res=solve(perm);
give_answer(res.size());
//for(int i:res)cout<<i<<" ";
//cout<<queries<<"\n";
return 0;
}
