#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<bitset>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<list>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<functional>
#include<cstdio>
#include<cstdlib>
#include<numeric>
//#include<atcoder/all>
using namespace std;
//using namespace atcoder;

#define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repr(i, 0, n)
#define INF 2e9
#define MOD 1000000007
//#define MOD 998244353
#define LINF (long long)4e18
#define jck 3.141592
#define PI acos(-1.0)

const double EPS = 1e-10;

using ll = long long;
using Pi = pair<int,int>;
using Pl = pair<ll,ll>;

ll square_sum(int a){
    return (ll)sqrt(a);
}

int main(){
    int n; cin >> n;
    ll ans = 0;
    vector<ll> to_prod(n+1);
    vector<bool> prime(n+1,true);
    for(ll i = 2; i*i <= n; i++){
        if(!prime[i]) continue;
        for(int j = i+i; j <= n; j+=i){
            prime[j] = false;
        }
    }
    repr(i,1,n+1) to_prod[i] = i;
    for(ll i = 2; i*i <= n; i++){
        if(prime[i]){
            ll k = i*i;
            for(ll j = k; j <= n; j+=k){
                while(to_prod[j]%k==0) to_prod[j] /= k;
            }
        }
    }
    repr(i,1,n+1){
        if(to_prod[i] <= n){
            ans += square_sum(n/to_prod[i]);
        }
    }
    cout << ans << endl;

}