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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
 
    long long N; cin >> N;
    int Need = 200000;
    vector<bool> prime(Need+1,true);
    prime.at(0) = false; prime.at(1) = false;
    for(int i=2; i*i<=Need; i++){
        if(!prime.at(i)) continue;
        for(int k=i*i; k<=Need; k+=i) prime.at(k) = false;
    }
    long long answer = 0;
    for(long long a=2; a*a<=N; a++) if(prime.at(a)){
        long long v = a*a;
        while(v <= N) answer += v,v *= a;
    }
    cout << answer << endl;
}