#include <iostream>
#include <numeric>
#include <vector>

using namespace std;
using lint = long long;

void solve() {
    lint n;
    cin >> n;

    vector<int> xs(n + 1);
    iota(xs.begin(), xs.end(), 0);

    for (int k = 2; k * k <= n; ++k) {
        auto s = k * k;
        if (xs[s] != s) continue;

        for (int x = s; x <= n; x += s) {
            while (xs[x] % s == 0) xs[x] /= s;
        }
    }

    vector<int> cnt(n + 1, 0);
    for (int x = 1; x <= n; ++x) ++cnt[xs[x]];

    lint ans = 0;
    for (auto c : cnt) ans += lint(c) * c;
    cout << ans << "\n";
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();

    return 0;
}