#include <bits/stdc++.h>

using namespace std;
using ll = long long;

vector<ll> prime(8001, 1), odd(5e7+1);

void erat(long long N){
    prime[0] = 0;
    prime[1] = 0;
    iota(odd.begin(), odd.end(), 0);
    for (long long i=2; i*i<=N; i++){
        if (prime[i]){
            for (long long j=i*2; j <= 8000; j+=i){
                prime[j] = 0;
            }
            ll q=1;
            while(i*i<=N/q){
                q*=i*i;
                for (ll j=q; j<=N; j+=q){
                    odd[j] /= (i*i);
                }
            }
        }
    }
}

int main(){

    ll N, ans=0;
    cin >> N;
    erat(N);
    for (ll i=1; i<=N; i++){
        ans += floor(sqrt(N/odd[i]));
    }

    cout << ans << endl;

    return 0;
}