#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
//using mint = modint1000000007;
typedef long long ll;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> T;
template<typename T>bool chmax(T& a, const T& b) { if (a < b) { a = b;return true; } else { return false; } }
template<typename T>bool chmin(T& a, const T& b) { if (a > b) { a = b;return true; } else { return false; } }
template<class... Args> void dbg(Args&&... args) { ((cout << args << ' '), ...);cout << '\n'; }

const int di[] = { -1,0,1,0 };
const int dj[] = { 0,-1,0,1 };
const long long INF = 6000000000000000000;
const int inf = 1001001001;

vector<bool> Eratosthenes(int N) {
    vector<bool> isprime(N + 1, true);
    isprime[0] = isprime[1] = false;
    for (int p = 2; p <= N; ++p) {
        if (!isprime[p]) continue;
        for (int q = p * 2; q <= N; q += p) {
            isprime[q] = false;
        }
    }
    return isprime;
}

int main(void) {
    ll n; cin >> n;
    ll ans = 0;
    vector<bool> era = Eratosthenes(100000);
    for (ll i = 0; i <= 100000; i++) {
        if (era[i]) {
            ll cnt = i * i;
            while (cnt <= n) {
                ans += cnt;
                cnt *= i;
            }
        }
    }
    cout << ans << "\n";
}