// CTI
#include <bits/stdc++.h>

using namespace std;

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

int main()
{
	//ios::sync_with_stdio(false);
	//cin.tie(0);

	int n; in >> n;
   vector<int> v(n+1);
   for (int i = 1; i <= n; ++i) {
      v[i] = i - 1;
   }

   for (int i = 1; i <= n; ++i) {
      for (int j = 2*i; j <= n; j += i) {
         v[j] = v[j] - v[i];
      }
   }

   long long answer = 0;
   for (int i=1; i<=n; ++i) {
      answer += v[i] * 2;
   }
   answer += 1;

   out << answer << '\n';

	return 0;
}