//Include
#include <fstream>
using namespace std;

//Definitii
#define ll long long int

//Constante
const int MAX_SIZE = (int)1e6+1;

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

int n;
int v[MAX_SIZE];
ll rasp;

//Main
int main()
{
	in >> n;
	for(int i=1 ; i<=n ; ++i)
		v[i] = i-1;
	
	for(int i=2 ; i<=n ; ++i)
	{
		for(int j=i<<1 ; j<=n ; j+=i)
			v[j] -= v[i];
		rasp += v[i];
	}
	
	out << (rasp << 1) + 1;
	
	in.close();
	out.close();
	return 0;
}