#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;

const int INF = 2e9;
const ll LINF = 2e18;

#define rep(i, n) for (int i = 0; (i) < (n); (i)++)
#define rep1(i, n) for (int i = 1; (i) < ((n) + 1); (i)++)
#define all(a) (a).begin(), (a).end()

const int dx[] = {-1,0,1,0};
const int dy[] = {0,1,0,-1};

int main(){
  ll N;
  cin>>N;
  bool isprime[100009];
  rep1(i,100000) isprime[i] = true;
  isprime[0] = false;
  isprime[1] = false;
  for(int i = 2; i < 1000; i++){
    for(int j = 2; i * j <= 100000; j++){
      isprime[i*j] = false;
    }
  }

  ll ans = 0;
  rep1(i,100000){
    if(isprime[i]){
      ll t = i;
      while(t*i <= N){
        t*=i;
        ans+=t;
      }
    }
  }

  cout<<ans<<endl;
}