#include <iostream>
using namespace std;

int main() {
	unsigned long long int n;
	int fizzbuzzstring;
	fizzbuzzstring = 0;
	cin >> n;
	int t;
	t = 1;
	while (t <= n) {
		if (t % 3 == 0)
			fizzbuzzstring = fizzbuzzstring + 2;
		if (t % 5 == 0)
			fizzbuzzstring = fizzbuzzstring + 2;
		t++;
	}
	cout << fizzbuzzstring << endl;
	return 0;
}