#include<stdio.h>
long n;
long long nr;
FILE *f=fopen("fractii.in","r");
FILE *g=fopen("fractii.out","w");



long cmmdc(long d,long i)
{  long r;
 r=d%i;
  while(r)
   {d=i;
   i=r;
   r=d%i;
   }
 return i;



}

void rez()
{
  long i,j;
 nr=0; 
  nr+=2*n-1;
 for(i=2;i<=n-1;i++)
 for(j=i+1;j<=n;j++)
  if((cmmdc(i,j)==1&&i!=j))
   nr+=2;
}

  


int main()
{ 
  fscanf(f,"%ld",&n);
   rez();
  fprintf(g,"%ld",nr);
 return 0;
}