#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main()
{
    int64_t n, ans=0;
    int i, j, k;
    bool flg = true;
    vector<int> sosu;

    cin >> n;

    int n_ma = sqrt(n);
    for (i=2; i<=n_ma; i++) {
        if (i == 2){
            sosu.push_back(i);
            k = 2;
            while (pow(i, k) <= n) {
                ans += pow(i, k);
                k++;
            }
            continue;
        }

        for (j=0; j<sosu.size(); j++) {
            if (i % sosu[j] == 0) {
                flg = false;
                break;
            }
        }

        if (flg) {
            sosu.push_back(i);
            k = 2;
            while (pow(i, k) <= n) {
                ans += pow(i, k);
                k++;
            }
            
        }
        flg = true;
    }

    cout << ans << endl;
}