#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
template<typename T> using pq = priority_queue<T>;
template<typename T> using pq_g = priority_queue<T, vector<T>, greater<T>>;
using mint = modint998244353;
// using mint = modint1000000007;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define unique(v) (v).erase(unique(all(v)), (v).end())
#define NP next_permutation
#define endl "\n"
#define debug(x) cerr << #x << " = " << (x) << endl
const int INF = 2e9;
const ll LINF = 2e18;
void Yes(bool a) {cout << (a ? "Yes" : "No") << endl;}
void YES(bool a) {cout << (a ? "YES" : "NO") << endl;}
void Possible(bool a) {cout << (a ? "Possible" : "Impossible") << endl;}
void POSSIBLE(bool a) {cout << (a ? "POSSIBLE" : "IMPOSSIBLE") << endl;}
ll modPow(ll a, ll n, ll mod = LINF) {ll ret = 1; ll x = a % mod; while (n) {if (n & 1) ret = ret * x % mod; x = x * x % mod; n >>= 1;} return ret;}
template<typename T> T floor(T a, T b) {return a / b - (a % b && (a ^ b) < 0);}
template<typename T> T ceil(T a, T b) {return floor(a + b - 1, b);}
template<typename T> void vcin(vector<T> &a) {rep(i, int(a.size())) cin >> a[i];}
template<typename T, typename K> void vcin(vector<T> &a, vector<K> &b) {rep(i, int(a.size())) cin >> a[i] >> b[i];}
template<typename T> void vcout(vector<T> &a) {rep(i, int(a.size())) {cout << a[i] << " ";} cout << endl;}
template<typename T> void vcin(vector<vector<T>> &a) {rep(i, int(a.size())) rep(j, (int)a[i].size()) cin >> a[i][j];}
template<typename T> void vcout(vector<vector<T>> &a) {rep(i, int(a.size())) {rep(j, int(a[i].size())) {cout << a[i][j] << " ";} cout << endl;} cout << endl;}
template<typename T> auto vmin(vector<T> &a) {return *min_element(all(a));}
template<typename T> auto vmax(vector<T> &a) {return *max_element(all(a));}
template<typename T> auto vsum(vector<T> a) {return accumulate(all(a), T(0));}
template<typename T> bool chmin(T &a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T &a, T b){if(a < b){a = b; return true;} return false;}

void cincout() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(15);
}

vector<int> Eratosthenes(int n) {
    vector<bool> isPrime(n + 1, true);
    vector<int> Prime;
    isPrime[0] = false;
    isPrime[1] = false;

    for (int i = 2; i * i <= n; i++) {
        if (!isPrime[i]) continue;
        for (int j = i * i; j <= n; j += i) {
            isPrime[j] = false;
        }
    }

    for (int i = 2; i <= n; i++) if (isPrime[i]) Prime.push_back(i);
    return Prime;
}
 
int main() {
    cincout();

    ll n;
    cin >> n;
    auto Prime = Eratosthenes(1e5);
    ll ans = 0;
    for (auto &p : Prime) {
        ll cur = p;
        while (cur * ll(p) <= n) {
            cur *= p;
            ans += cur;
        }
    }

    cout << ans << endl;
}