#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  ll n;
  cin >> n;
  vector<bool> is_prime(100'001, true);
  is_prime[0] = is_prime[1] = false;
  ll ans = 0;
  for (ll i = 2; i * i <= n; ++i) {
    if (!is_prime[i]) continue;
    for (ll j = i * i; j <= 100'000; j += i) is_prime[j] = false;
    ll x = i * i;
    while (true) {
      ans += x;
      if (x > n / i) break;
      x *= i;
    }
  }
  cout << ans << '\n';
  return 0;
}