#include <iostream>
using namespace std;

int main() {
	int n, t = 0;
	cin >> n;
	for(int i = 1;i < n + 1;++i){
	   for(int j = 2;j < i;++j){
	   	if(i / j == 0) break;
	   	if(j == i - 1) t++;
	   }	
	}
	cout << t << endl;
	return 0;
}