#include<fstream.h>   
#include<math.h>   
  
unsigned long n,c,i;   
unsigned int d,ok;   
  
int prim(int);   
  
int main()
{
    ifstream In("ciur.in");
    ofstream Out("ciur.out");
    In>>n;
    In.close();
    for(i=1;i<=n;i++)
    {
	if( (i%2) || (i%3) ) continue;
	else if(prim(i)) c++;
    }
    Out<<c<<'\n';   
    Out.close();   
    return 0;   
}   
  
int prim(int x)   
{   
    ok=1;   
    for(d=2;d<=sqrt(n);d++)   
    {   
         if(x%d==0) {ok=0;break;}   
    }   
    return ok;   
}