/*#include<iostream>
#include<fstream>
using namespace std;
int main()
{
  //ifstream f1("vector.in");
  //ofstream f2("vector.out");
   int n , v[100];
   cin>>n;
   for(int i=1;i<=n;i++)
   {
     cin>>v[i];
   }	
   int aux;
   for(int i=1;i<=n-1;i++)

	   for(int j=i+1;j<=n;j++)
		   
		    if((v[i] % 100) > (v[j] % 100))
			{
			  aux= v[i];
			  v[i] =v[j];
			  v[j] = aux;
			}
   
   for(int i=1;i<=n;i++)
	   cout<<v[i]<<endl;
  
  return 0;
}*/
/*
#include <iostream>

using namespace std;
int main()
{
 int n, v[100];
 float medie = 0;
 cin>>n;
  for(int i=1;i<=n;i++)
     cin>>v[i];
  int c = 0;
  for(int i=1;i<=n;i++)
  {
     medie = medie + v[i];
	 c = c + 1;
  }
  cout<<"Medie = "<<float(medie/c);      	  
 return 0;
}*/
/*
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int main()
{
     ifstream in("cifra.in");
	 ofstream out("cifra.out");
	  
	 int n ,verf;
	 in>>n;
	 int suma = 0 , r =0 , mod ,c;
     
	 for(int i=1;i<=n;i++)
	 {
	     in>>verf;
		 c = 0;
		 while(c != verf)
		 {
		   c = c + 1;
		   r = r + 1;
		   mod = pow(r , r);
		   suma= suma + mod;
		 }
		 out<<suma%10<<endl;
		 r = 0;
		 suma = 0;
		 
	 }
	 return 0;
}*/
/*
#include <iostream>
#include <fstream>
#include <string>

using namespace std;
int main()
{
  ifstream in("vector.in");
  ofstream out("vector.out");
  string name[50];
  int n;
  float nr[50];
  in>>n;
  for(int i=1;i<=n;i++)
  {
     in>>name[i];
     in>>nr[i];	 
  }
  float aux;
  string aux2;
  for(int i=1;i<=n+1;i++)
	  for(int j=i+1;j<=n;j++)
	  {
	     if(nr[i] < nr[j])
		 {
			aux2 = name[i];
			name[i] = name[j];
            name[j] = aux2;			
			 
		    aux = nr[i];
			nr[i] = nr[j];
			nr[j] = aux;
		 }
	  }
	  
   for(int i=1;i<=n;i++) out<<name[i]<<" "<<nr[i]<<endl;	  
  return 0;
}
*/
/*
#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int main()
{
  ifstream in("dreptunghi.in");
  ofstream out("dreptunghi.out");
  int N , Q  , a , b;
  in>>N;
  in>>Q;
  int j , nr =0 ,  c =0;
  for(int i=1;i<=Q;i++)
  {
	  c = 0;
	  in>>a;
	  in>>b;
	  j = a;
	  while(j<=b)
      {   
		 nr = 0;
		  for(int i=2;i<=b;i++)       
		    if(j % i == 0) nr = nr + 1;
	      j = j + 1;
		  if(nr == 1) c = c + 1;
		  
      }	
    out<<c<<endl;	 
    }
   
}*/
/*#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
int main()
{
  ifstream in("dreptunghi.in");
  ofstream out("dreptunghi.out");
  int N , Q  , a , b;
  in>>N;
  in>>Q;
  int j , nr =0 ,  c =0;
  for(int i=1;i<=Q;i++)
  {
	  c = 0;
	  in>>a;
	  in>>b;
	  j = a;
	  while(j<=b)
      {   
		 nr = 0;
		  for(int i=2;i<=b;i++)       
		    if(j % i == 0) nr = nr + 1;
	      j = j + 1;
		  if(nr == 1) c = c + 1;
		  
      }	
    out<<c<<endl;	 
    }
   
}*/
/*
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
  ifstream in("adunare.in");
  ofstream out("adunare.out");
  int a, b;
  in>>a;
  in>>b;
  out<<a+b;
  
   
}*/
/*
#include<iostream>
#include<fstream>

using namespace std;
int main()
{
   ifstream in("cmmdc.in");
   ofstream out("cmmdc.out");
   int a, b ,i = 0 ,tr = 1;
   in>>a;
   in>>b;
   out<<a;
   return 0;
}*/
#include <fstream>
#include  <iostream>
using namespace std;
int main()
{
	ifstream in("fractii.in");
	ofstream out("fractii.out");
	
	int nr = 0, N ,v[100];
	in>>N;
	for(int i=2;i<=N;i++)
	{
	  v[i] = i - 1;
	}
	for(int i = 2;i<=N;i++)
      {
		  for(int j = i + i ; j<=N;j = j + i)v[j] = v[j] - v[i];
	     nr = nr + v[i];
	   }
    nr = nr * 2 + 1;
	out<<nr;
    return 0;
}