#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)
typedef long long ll;

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

	ll ans = 0;
	ans += (N / 3) * 2;
	ans += (N / 5) * 2;
	cout << ans << endl;
}