#include <iostream>
using namespace std;

int main() {
  long long N;
  cin >> N;
  int z[15] = {0, 0, 0, 2, 2, 4, 6, 6, 6, 8, 10, 10, 12, 12, 12};
  cout << N / 15 * 16 + z[N % 15] << endl;
}