using namespace std;
#ifdef EZ
   #include "./ez/ez.h"
   const string FILE_NAME = "test";
#else
   #include <bits/stdc++.h>
   const string FILE_NAME = "fractii";
#endif
#define mp make_pair
#define ll long long
#define pb push_back
#define fi first
#define se second
#define cin fin
#define cout fout
ifstream fin (FILE_NAME + ".in");
ofstream fout (FILE_NAME + ".out");

int M[1'000'001];

int main()
{
   int n;   cin >> n;

   M[1] = 1;
   for(int i = 1; i <= n; i++)
      for(int j = i + i ; j <= n; j += i)
         M[j] -= M[i];

   ll ans = 0;
   for (int d = 1; d <= n; ++d)
      ans += 1LL * (n/d)*(n/d) * M[d];
   
   cout << ans;
}