#include <bits/stdc++.h>
using namespace std;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	long long n; cin >> n;
	long long three = (n / 3) * 2;
	long long five = (n / 5) * 2;
	cout <<  three + five << endl;
	return 0;	
}