#include <bits/stdc++.h>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

int main() {
  int64_t n;
  cin >> n;
  cout << n / 3 * 2 + n / 5 * 2 << endl;
}