#include<bits/stdc++.h>
using namespace std;
long long a[100000001];
bool ok() {
    for(long long i = 0; i <= 1000001; i++)
        a[i] = 1;
        a[0] = a[1] =0;
        for(long long i = 2; i <= 1000; i++) {
            if(a[i]){
                for(long long j=i*i; j <= 1000000; j+=i) {
                    a[j]=0;
                }
            }
    }
}
int main(){
    freopen("BEAUNUM.inp","r",stdin);
   freopen("BEAUNUM.out","w",stdout);

    ok();
    long long n,i,d=0;
    cin>>n;
    for( i=0;i<=n; i++){
        if (a[i]) {
        if (i*i*i*i > n ) break;
        d=d+1;
        }
    }
    cout<<d<<endl;
    return 0;
}