// No.311 z in FizzBuzzString
// https://yukicoder.me/problems/no/311
//

#include <iostream>
using namespace std;

unsigned long solve(unsigned long N);


int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    unsigned long N;
    cin >> N;
    unsigned long ans = solve(N);
    cout << ans << endl;
}

unsigned long solve(unsigned long N) {
    unsigned long fizz = N / 3;
    unsigned long buzz = N / 5;
    return fizz * 2 + buzz * 2;
}