#include <bits/stdc++.h>
#include "trilib.h"
using namespace std;
/*int get_n()
{
return 6;
}
bool is_clockwise(int a,int b,int c)
{
cout << "query: " << a << " " << b << " " << c << endl;
int res;
cin >> res;
return res;
}
void give_answer(int s)
{
cout << "answer: " << s << endl;
exit(0);
}*/
int main()
{
int n=get_n();
vector<int> l,r;
for(int i=3;i<=n;i++)
{
if(is_clockwise(1,2,i)) r.push_back(i);
else l.push_back(i);
}
sort(l.begin(),l.end(),[](int a,int b){return is_clockwise(1,a,b);});
sort(r.begin(),r.end(),[](int a,int b){return is_clockwise(1,a,b);});
reverse(l.begin(),l.end());
vector<int> one={1,2};
for(int a:l)
{
while(one.size()>=2&&is_clockwise(one[one.size()-2],one.back(),a)) one.pop_back();
one.push_back(a);
}
vector<int> two={1,2};
for(int a:r)
{
while(two.size()>=2&&is_clockwise(two[two.size()-2],two.back(),a)==0) two.pop_back();
two.push_back(a);
}
int res=one.size()+two.size()-2;
if(min(one.size(),two.size())>=3&&is_clockwise(2,one[2],two[2])) res--;
if(min(one.size(),two.size())>=3&&is_clockwise(1,one.back(),two.back())==0) res--;
give_answer(res);
return 0;
}
