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

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll n;
    cin >> n;
    constexpr int r = 100'000;
    vector<bool> tb(r + 1);
    unsigned long long ans = 0;
    for(int i = 2; i <= r; i++){
        if(tb[i]) continue;
        ll v = (ll)i * i;
        if(v > n) break;
        while(v <= n){
            ans += v;
            v *= i;
        }
        for(int j = 2 * i; j <= r; j += i) tb[j] = true;
    }
    cout << ans << '\n';
}