#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <tuple>
#include <cstdio>
#include <cassert>
#include <atcoder/modint>
#define rep(i, n) for(i = 0; i < n; i++)
#define int long long
using namespace std;
using namespace atcoder;

bool isprime[100001];

signed main() {
    int n;
    cin >> n;

    int i, j;
    for (i = 2; i <= 100000; i++) isprime[i] = true;
    for (i = 2; i <= 100000; i++) {
        if (isprime[i]) {
            for (j = i * 2; j <= 100000; j += i) isprime[j] = false;
        }
    }

    int ans = 0;
    for (i = 2; i <= 100000; i++) {
        if (!isprime[i]) continue;
        int mul = i * i;
        while (mul <= n) {
            ans += mul;
            mul *= i;
        }
    }

    cout << ans << endl;
    return 0;
}