#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;
    VI d(n + 1);
    d[1] = 1;
    VI lpf(n + 1);
    VI ps;
    ps.reserve(n / 10);
    for(int p = 2; p <= n; p++) {
        if (lpf[p] == 0) {
            d[p] = p;
            ps.push_back(p);
        }
        int v = d[p];
        for(int q: ps) {
            ll t = (ll)p * q;
            if (t > n || q > p) break;
            lpf[t] = q;
            if (v % q == 0) d[t] = v / q;
            else d[t] = v * q;
        }
    }
    VI hist(n + 1);
    for(int i = 1; i <= n; i++) hist[d[i]]++;
    ll ans = 0;
    for(int i = 1; i <= n; i++) ans += (ll) hist[i] * hist[i];
    cout << ans << '\n';
}