#include<fstream.h>
#include<math.h>  
ifstream fin("fractii.in");    
ofstream fout("fractii.out");    
long long a[10000001],n,s,i,j;
int main()  
{    
	fin>>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];    
   }    
   fout<<2*s+1;    
   return 0;    
   }