#include <stdio.h>
int n,i,j,k,d,nr;
int main()
{
    freopen("ciur.in","r",stdin);
    freopen("ciur.out","w",stdout);
    scanf("%d",&n);
    j=0;
    nr=0;
    for(i=1;i<=n;i++)
    {
     d=0;
     for(k=1;k<=i;k++)
     {
      if(i%k==0) d++;
     }
     if(d>2) ;
     else nr++;
    }
    nr=nr-1;
    printf("%d",nr);
    return 0;
}