#include <iostream>
#include <algorithm>

using namespace std;
using ll = long long int;

int main()
{
    ll N;
    cin >> N;

    ll num_3 = N / 3;
    ll num_5 = N / 5;

    ll ans = num_3 * 2 + num_5 * 2;

    cout << ans << endl;
         
    return 0;
}