#include <iostream>
using namespace std;
int main(){
	int n , i , j;
	while(cin >> n ){
		int counter = 0;
		for( int i=1 ; i<=n ; i++ ){
			if( i%2 == 0 ){
				continue ;
			}
			int x = i;
			if( i>=6 )
				x = x /2;
			int temple=0;
			for( int j=1 ; j<=x ; j++ ){
				if( i%j == 0 )
					temple++;
			}
			if( temple == 2 )
				counter ++;
		}
		cout << counter << endl;
	}
}