#include <bits/stdc++.h>
#include "trilib.h"
using namespace std;
#define sz(x) ((int)size(x))
#define all(x) begin(x), end(x)
#define trace(x) cout << #x << ": " << (x) << endl;
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) { return (int) ((ll) rnd() % (r - l + 1)) + l; }
const int N = 40000;
const ll infL = 3e18;
int n;
bool ask(int i, int j, int k) {
return is_clockwise(i + 1, j + 1, k + 1);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
n = get_n();
vector<int> ord(n), side(n);
//0 - left, 1 - right
iota(all(ord), 0);
for (int i = 2; i < n; ++i) {
side[i] = ask(0, 1, i);
}
stable_sort(2 + all(ord), [&side](int i, int j) {
if (side[i] != side[j]) {
return side[i] < side[j];
}
return ask(0, i, j);
});
for (int i = 2; i < sz(ord); ++i) {
if (i == sz(ord) - 1 || (side[ord[i]] == 0 && side[ord[i + 1]] == 1)) {
rotate(begin(ord) + 1, begin(ord) + 2, begin(ord) + i + 1);
break;
}
}
deque<int> st;
for (int i : ord) {
while (sz(st) > 1 && !is_clockwise(st.end()[-2] + 1, st.back() + 1, i + 1)) {
st.pop_back();
}
st.push_back(i);
}
while (sz(st) > 3) {
if (!is_clockwise(st.end()[-2] + 1, st.end()[-1] + 1, st[0] + 1)) {
st.pop_back();
} else if (!is_clockwise(st.end()[-1] + 1, st[0] + 1, st[1] + 1)) {
st.pop_front();
} else {
break;
}
}
cout << sz(st);
return 0;
}
