#include <bits/stdc++.h>
using namespace std;
#define ALL(x) (x).begin(), (x).end()
#define REP(i,n) for(int i=0; i<n; i++)
bool chmax(auto& a, auto b) { return a<b ? a=b, true : false; }
bool chmin(auto& a, auto b) { return a>b ? a=b, true : false; }
using ll=long long; const int INF=1e9+10; const ll INFL=4e18;

#ifdef DEBUG
#include "./debug.hpp"
#else
#define debug(...)
#define print_line
#endif


/// @brief 素数列挙
/// @details n 以下の素数の配列を返す
/// @note O(n log(log(n)))
vector<int> PrimeEnumerate(int n) {
    vector<int> prime, is_prime(n+1,true);
    is_prime[0]=is_prime[1]=false;
    for(int i=2; i<=n; i++) {
        if(is_prime[i]) {
            prime.push_back(i);
            for(int j=2*i; j<=n; j+=i) is_prime[j]=false;
        }
    }
    return prime;
}

//----------------------------------------------------------

void solve() {
    ll N; cin>>N;

    const int mx=2e5;
    auto pr=PrimeEnumerate(mx);
    ll ans=0;
    for(ll p: pr) {
        ll cur=p*p;
        while(cur<=N) {
            ans+=cur;
            cur*=p;
        }
    }

    cout<<ans<<endl;
}

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    //cout<<fixed<<setprecision(15);
    int T=1; //cin>>T;
    while(T--) solve();
}