#include <stdio.h>     
	int main (){
	long i,j,n,s,a[1000010];  
	freopen ("fractii.in","r",stdin);     
	freopen ("fractii.out","w",stdout);     
	scanf ("%ld",&n);     
	for (i=0;i<=n;i++)     
		a[i]=i-1;     
	for (i=2;i<=n;i++)
		for (j=i*2;j<=n;j=j+i)     
			a[j]=a[j]-a[i];
	for (i=1;i<=n;i++)     
		s=s+a[i];     
	printf ("%ld",2*s+1);     
	return 0;     
}