#include<iostream.h>
#include<math.h>
#include<fstream.h>
 ifstream fin("fractii.in");
 ofstream fout("fractii.out");
long i,j,n,nrfrac;

long cmmdc(long a,long b)
{
 long r;
 do
 {
  r = a % b;
  a = b;
  b = r;
 }
 while(r);
 return a;
}

int main()
{
 fin>>n;
 nrfrac=1;
 for(i=1;i<=n;i++)
  for(j=1;j<=i;j++)
   if(cmmdc(i,j)==1 && i!=j) nrfrac++;
 fout<<2*nrfrac-1<<endl;
	return 0;
}