#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
#define all(a) begin(a), end(a)
#define rep(i, s, e) for (int i = s; i < e; ++i)
#define asort(a) stable_sort(all(a))
#define rsort(a) stable_sort(rbegin(a), rend(a))
#define sum(a) reduce(all(a))
#define min_(a) reduce(all(a), *begin(a), [](auto x, auto y) { return min(x, y); })
#define max_(a) reduce(all(a), *begin(a), [](auto x, auto y) { return max(x, y); })
constexpr double degrees(double a) { return (a * 180.0) / M_PI; }
constexpr double radians(double a) { return (a * M_PI) / 180.0; }

vector<ll> Eratosthenes(const ll n) {
  vector<bool> is_prime(n + 1);
  for (ll i = 0; i <= n; ++i) {
    is_prime[i] = true;
  }
  vector<ll> p;
  for (ll i = 2; i <= n; ++i) {
    if (is_prime[i]) {
      for (ll j = 2 * i; j <= n; j += i) {
        is_prime[j] = false;
      }
      p.emplace_back(i);
    }
  }
  return p;
}

int main(int, [[maybe_unused]] char *argv[]) {
#ifdef DEBUG
  freopen(argv[1], "r", stdin);
#endif

  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(15);

  ll N;
  cin >> N;
  vector<ll> p = Eratosthenes(100000);
  ll ans = 0;
  ll x;
  for (ll i = 2; i < N; ++i) {
    if (pow(2, i) > N) break;
    for (ll j : p) {
      x = pow(j, i);
      if (x <= N) {
        ans += x;
      } else {
        break;
      }
    }
  }
  cout << ans << endl;
  return 0;
}