#include <iostream>

using namespace std;

using LL = long long;

int main() {
  LL N;
  cin >> N;

  LL ans = 0L;
  for (LL i = 0L; i < N; ++i) {
    if (i % 3 == 0) {
      ans += 2;
    }
    if(i % 5 == 0) {
      ans += 2;
    }
  }
  cout << ans << endl;
}