#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P  = pair <int, int>;

#define rep(i, n)     for (int i = 0; i < (int) (n); i++)
#define repr(i, a, b) for (int i = a; i < b; i++)
#define each(i, mp)   for (auto &i : mp)

const int INF = 1001001001;

int main()
{
  int a;
  cin >> a;
  ll ans = 0;

  rep(i, 3) ans += pow(a, i + 1);
  cout << ans << endl;

  return 0;
}

#include <bits/stdc++.h>
using namespace std;
#define ALL(a) (a).begin(),(a).end()
#define rALL(a) (a).rbegin(),(a).rend()
typedef pair<int, int> Pint;
typedef pair<int64_t, int64_t> Pll;


int main() {
    int N;
    cin >> N;
    cout << (N - 2) * 180 << endl;
}

