#include <iostream>
#include <vector>
#include <algorithm>
#include <string>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)
#define dump(val) cerr << __LINE__ << ":\t" << #val << " = " << (val) << endl

using namespace std;

typedef long long int lli;

template<typename T>
vector<T> make_v(size_t a, T b) {
    return vector<T>(a, b);
}

template<typename... Ts>
auto make_v(size_t a, Ts... ts) {
    return vector<decltype(make_v(ts...))>(a, make_v(ts...));
}

int main() {
    int N;
    cin >> N;
    vector<bool> isPrime(N + 1, true);
    vector<int> Prime;
    isPrime[0] = isPrime[1] = false;
    REP(i, 2, N + 1) {
        if (isPrime[i]) {
            Prime.push_back(i);
            for (int j = 2 * i; j < N + 1; j += i) {
                isPrime[j] = false;
            }
        }
    }

    const int PSZ = Prime.size();
    vector<int> memo(PSZ, 0);
    REP(i, 2, N + 1) {
        vector<int> plst;
        REP(j, 0, PSZ) {
            if (i % Prime[j] == 0 && memo[j] != 0) {
                plst.push_back(memo[j]);
            }
        }
        sort(begin(plst), end(plst));
        plst.erase(unique(begin(plst), end(plst)), end(plst));
        int cnt = 0;
        for (int &n : plst) {
            cnt += n;
        }
        if (i > cnt) {
            REP(j, 0, PSZ) {
                if (i % Prime[j] == 0) {
                    memo[j] = i;
                }
            }
        }
    }
    sort(begin(memo), end(memo));
    memo.erase(unique(begin(memo), end(memo)), end(memo));
    int ans = 0;
    for (int &n : memo) {
        ans += n;
    }
    cout << ans << endl;
    return 0;
}