#include <bits/stdc++.h>
#include "trilib.h"
using namespace std;
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define per(i, a, b) for (int i = b - 1; i >= (a); --i)
#define trav(a, x) for (auto &a : x)
#define all(x) x.begin(), x.end()
#define sz(x) x.size()
#define pb push_back
#define umap unordered_map
#define uset unordered_set
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef long long ll;
const int INF = 1000000007;
vi fibs;
int main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);
int n=get_n();
if (50 < n) return 0;
int arr[n][n][n];
rep(i, 0, n) rep(j, 0, n) {
if (i == j) continue;
rep(k, 0, n) {
if (i == k || j == k) continue;
arr[i][j][k] = is_clockwise(i + 1, j + 1, k + 1);
}
}
int city = 0, layer[n], cur = 0;
memset(layer, -1, n * 4);
while (1) {
if (layer[city] != -1) {
give_answer(cur - layer[city]);
break;
}
layer[city] = cur++;
int nxt = -1;
rep(j, 0, n) {
rep(k, 0, n) {
if (j == city || k == city || j == k) continue;
if (!arr[city][j][k]) {
nxt = j;
break;
}
}
if (nxt != -1) break;
}
int cnt=0;
bool stop = 0;
while (!stop) {
++cnt;
stop = 1;
rep(k, 0, n) {
if (k == city || k == nxt) continue;
if (!arr[city][k][nxt]) {
nxt = k;
stop=0;
break;
}
}
}
city = nxt;
}
return 0;
}
