#include<fstream>
#include<math.h>

using namespace std;

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

int n , nr;
int V[1000010];

int main(){
	
	f>>n;
	
	for( int i = 1 ; i <= n ; i++ )
		V[i] = i - 1;
	
	for( int j , i = 2 ; i <= n ; i++ )
		for( j = i+i ; j <= n ; j += i )
			V[j] -= V[i];
	
	for( int i = 2 ; i <= n ; i++ )
		nr += V[i];
	
	g<< 2 * nr + 1 <<"\n";
	
	return 0;
}