#include <iostream>
#include <cstdlib>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iostream>
#include <iomanip>
#include <deque>

int main()
{
    long a;
    std::cin >> a;
    std::cout << 2 * (a / 3 + a / 5) << std::endl;
    return 0;
}