#include <bits/stdc++.h>
using namespace std;
template <typename T>
T &chmin(T &a, const T &b) {
  return a = min(a, b);
}
template <typename T>
T &chmax(T &a, const T &b) {
  return a = max(a, b);
}
template <typename T>
T gcd(const T a, const T b) {
  return b ? gcd(b, a % b) : a;
}
template <typename T>
T lcm(const T a, const T b) {
  return a / gcd(a, b) * b;
}
template <typename T>
T ceil(const T a, const T b) {
  return (a + b - 1) / b;
}
template <typename T>
long double dist(const T x1, const T y1, const T x2, const T y2) {
  long double x = x1 - x2;
  long double y = y1 - y2;
  return sqrt(x * x + y * y);
}
template <typename T>
void aout(const T *a, const int n) {
  for (int i = 0; i < (n); ++i) cout << a[i] << ' ';
  cout << "\n";
}
template <typename T>
void vout(const vector<T> &v) {
  for (int i = 0; i < ((int)(v).size()); ++i) cout << v[i] << ' ';
  cout << "\n";
}
const int di4[4] = {-1, 0, 1, 0};
const int dj4[4] = {0, 1, 0, -1};
const int di8[8] = {-1, -1, 0, 1, 1, 1, 0, -1};
const int dj8[8] = {0, 1, 1, 1, 0, -1, -1, -1};
const int dik[8] = {2, 1, -1, -2, -2, -1, 1, 2};
const int djk[8] = {1, 2, 2, 1, -1, -2, -2, -1};
const int maxn = 100100;
const int mod = 1e9 + 7;
const int inf = INT_MAX;
const long double eps = 1e-9;
const long double pi = acos(-1.0);
int n;
void solve() {
  cin >> n;
  long long ans = (long long)(n - 2) * (n - 2);
  cout << (ans) << "\n";
}
void init() {}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout.precision(10);
  cout << fixed;
  int tc = 1;
  for (int i = 1; i <= (tc); ++i) {
    solve();
  }
  return 0;
}
