# 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;     
}