#include<bits/stdc++.h>
using namespace std;

vector<int> sieve(int n){
  vector<int> prime;
  vector<bool> isprime(n+1,true);
  isprime[1]=false;
  for (int i=2;i<=n;i++){
    if (!isprime[i]) continue;
    prime.push_back(i);
    for (int j=i*2;j<=n;j+=i){
      isprime[j]=false;
    }
  }
  return prime;
}

int main(){
  using ll=long long;
  ll n;
  cin>>n;
  auto ps=sieve(1e6);
  ll ans=0;
  for (ll p:ps){
    ll prod=p*p;
    while (prod<=n){
      ans+=prod;
      prod*=p;
    }
  }
  cout<<ans<<endl;
}