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

#define put(i) cout << i << endl

int main() {
    long long n, ans = 0; cin >> n;
    for (int i = 3; i <= n; i += 3) ans+=2;
    for (int i = 5; i <= n; i += 5) ans+=2;
    put(ans);
}