#include <bits/stdc++.h>
typedef long long int ll;
using namespace std;
ll ans = 0;

int main() {
  ll N;
  cin >> N;
  assert(2 <= N && N <= 10000000000);
  for (ll i = 2; i < 100000; i++) {
    bool is_div = false;
    for (ll j = 2; j <= sqrt(i); j++) {
      if (i % j == 0) {
        is_div = true;
        break;
      }
    }
    if (!is_div) {
      ll now = i * i;
      while (now <= N) {
        ans += now;
        now *= i;
      }
    }
  }
  cout << ans << endl;
  return 0;
}