#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
using ll = long long;

int main(void){
  ll n; cin >> n;
  int nn=1e5+1;
  vector<ll> yakusu(nn+1, -1), prime;
  for(int i=2; i<=nn; i++){
    if(yakusu[i]!=-1) continue;
    int copy=i;
    prime.push_back(i);
    while(copy<=nn){
      if(yakusu[copy]==-1) yakusu[copy]=i;
      copy+=i;
    }
  }
  ll ans=0;
  for(auto p:prime){
    if(p*p>n) break;
    ll now=p*p;
    while(now<=n) ans+=now, now*=p;
  }
  cout << ans << endl;
  return 0;
}