#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>

int main() {
  ll n;
  cin >> n;

  if (n < 3) cout << n << endl;
  else cout << (n-3)*5+3 << endl;


}