#include<bits/stdc++.h>
#define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define file freopen("BEAUNUM.inp","r",stdin);freopen("BEAUNUM.out","w",stdout);
using namespace std;
int main(){
 file;
 long long n,e=0,kq=0,bien=0;
 bool ktra[100000];
 memset(ktra,true,sizeof(ktra));
 ktra[0]=ktra[1]=false;
 for(int i=2;i*i<=1e5+5;i++)
  if (ktra[i])
   for (int j=i*i;j<=n;j+=i)
    ktra[j]=false;
 cin>>n;
 while (bien<n){
  e++;
  if (ktra[e]){
   bien=e*e*e*e;
   kq++;
  }
 }
 if (bien>n) kq--;
 cout<<kq;
 return 0;
}