#include <fstream>
using namespace std;
ifstream cin("ciur.in");
ofstream cout("ciur.out");
int main()
{
	unsigned int n, s=0;
		cin >> n;
		if (n == 3) s = 2;
		if (n == 2) s = 1;
		for (int i = n; i > 3; i--)
			if (i % 2 != 0 && i % 3 != 0) s++;
		cout << s;
		return 0;

}