#include<fstream>
using namespace std;
unsigned int c,i,phi[1000002],p;
int phi(int a)
{
	for (i=2;i<=a;i++)
		phi[i]=i-1;
	for (i=2;i<=a;i++)
		for (int c=2*i;c<=n;c+=i)
			phi[c] -= phi[i];
	p+=phi[i];
	return p;
}
int main()
{
	unsigned int n,m=0;
	ifstream f1("fractii.in");
	f1>>n;
	ofstream f2("fractii.out");
	for (i=2;i<=n;i++)
		m=m+phi(i);
	f2<<2*m+1;
	return 0;
}