#include<fstream.h>
ifstream f("fractii.in");  
ofstream g("fractii.out");  
long long a[1000001],n,s,i,j;
int main()
{  
	f>>n;  
	for(i=1;i<=n;i++)  
		a[i]=i-1;  
	s=0;  
	for(i=1;i<=n;i++)
		{  
			for(j=2*i;j<=n;j=j+i)  
				a[j]=a[j]-a[i];  
			s=s+a[i];  
		}  
	g<<2*s+1;  
return 0;  
}