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