#include <fstream>
using namespace std;

ifstream cin("fractii.in");
ofstream cout("fractii.out");

constexpr int N = 1e6 + 1;

int m[N+1];

int main()
{
    m[1] = 1; int n; cin >> n;
    for(int i = 1; i <= N ; i++)
        for(int j = i + i ; j <= N ; j += i)
            m[j] -= m[i];

    long long ans = 0;
    for(int i = 1; i <= n ; i++)
        ans += 1LL*m[i]*(n/i)*(n/i);

    cout << ans;
}