//#pragma option -3 -a -Z -O2 -r
#include<fstream.h>
unsigned long n;
int nrprime(unsigned long x,unsigned long y)
{unsigned long r;
 do
  {r=x%y;
   x=y;
   y=r;
  }
 while(r);
 if(x==1) return 1;
   else return 0;
}
int main()
{unsigned long i,j,c=0;
 ifstream f("fractii.in");
 ofstream g("fractii.out");
 f>>n;
 f.close();
 c=2*n-1;
 //cc=n/2;c3=1;
 for(i=2;i<=n;i++)
  {if(i%2==0)
     {for(j=i+1;j<=n;j=j+2)
      // /*if(nrprime(i,j))*/ c+=2;
      //c=c+(cc-c3)*2;c3++;
     }
    else
     {for(j=i+1;j<=n;j++)
       if(nrprime(i,j)) c+=2;
     }
  }
 g<<c<<'\n';
 g.close();
return 0;
}