#include<stdio.h>
#include<math.h>
long n;
long long nr,v[10000],k;
FILE *f=fopen("fractii.in","r");
FILE *g=fopen("fractii.out","w");



void prim()
{
 nr=2*n-1;
 k=0;
 v[++k]=2;
 long long i,j;
 int sw;

 for(i=3;i<=n;i++)
  {sw=1;
  for(j=2;j<=sqrt(i);j++)
      if(i%j==0)
       {sw=0;break;}
	if(sw)
     v[++k]=i;
 }

}
void rez()
{ long long i,j,x;
 int sw; 

 for(i=2;i<=n-1;i++)
    for(j=i+1;j<=n;j++)
   {
   sw=1;
   for(x=1;x<=k;x++)
    {if((i%v[x]==0&&j%v[x]==0))
      {sw=0;break;}
    if(j<v[x])
     break;
     }
 if(sw)
  nr+=2;
    }
 }

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