#include <bits/stdc++.h>

using namespace std;

using ll = long long;

bool is_prime(int n) {
    if (n % 2 == 0) return false;
    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0) return false;
    }
    return n != 1;
}

vector<int> divisor(int n) {
    vector<int> res;
    for (int i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            res.emplace_back(i);
            if (i != n / i) res.emplace_back(n / i);
        }
    }
    return res;
}

map<int, int> prime_factor(int n) {
    map<int, int> res;
    for (int i = 2; i * i <= n; i++) {
        while (n % i == 0) {
            ++res[i];
            n /= i;
        }
    }
    if (n != 1) res[n] = 1;
    return res;
}

vector<int> sieve(int n, vector<bool>& is_prime) {
    vector<int> res;
    is_prime.resize(n + 1, true);
    is_prime[0] = false;
    is_prime[1] = false;
    for (int i = 2; i <= n; i++) {
        if (!is_prime[i]) continue;
        res.emplace_back(i);
        for (int j = 2 * i; j <= n; j += i) is_prime[j] = false;
    }
    return res;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<int> ans;
    int sum = 0;
    for (int i = 2; i <= n; i++) {
        vector<int> hoge;
        int ts = 0;
        for (int x : ans) {
            int g = __gcd(x, i);
            if (g == 1) hoge.push_back(x);
            else {
                ts += x;
            }
        }
        if (i >= ts) {
            hoge.push_back(i);
            ans = move(hoge);
        }
    }
    for (int x : ans) {
        sum += x;
        //cout << x << endl;
    }
    cout << sum << endl;
    return 0;
}