#include <bits/stdc++.h>
using namespace std;
using ll=long long;
int main(){
	ll n;
	cin>>n;
	vector<ll> primes,lpf(100001,-1);
	ll ans=0;
	for(ll i=2;i<=100000;i++){
		if(lpf[i]==-1){
			primes.push_back(i);
			lpf[i]=i;
			ll x=i*i;
			while(x<=n){
				ans+=x;
				x*=i;
			}
		}
		for(ll p:primes){
			if(p*i>100000||p>lpf[i])break;
			lpf[p*i]=p;
		}
	}
	cout<<ans<<endl;
}