#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<bool> seen(n + 1);
    ll ans = 0;
    for(int i = 1; i <= n; i++) {
        if (seen[i]) continue;
        int cnt = 1;
        for(int j = 2; ; j++) {
            ll t = (ll)j * j * i;
            if (t > n) break;
            cnt++;
            seen[t] = true;
        }
        ans += (ll) cnt * cnt;
    }
    cout << ans << '\n';
}