#include <iostream>
#include <vector>
#include <math.h>
#include <stdio.h>
#include <algorithm>
#include <string>
#include <map>
#include <queue>
#define ll long long

int main() {
  ll N;
  std::cin >> N;
  ll count = N / 3 * 2 + N / 5 * 2;
  std::cout << count << std::endl;
}