type natural=0..1000000;


var n:natural;
    sum:int64;
    tab:array[1..1000000] of int64;
    
    Procedure Cit;
     var f:text;
     begin
      assign(f,'fractii.in');
      reset(f);
      read(f,n);
      close(f);
     end;

    Procedure Afis;
     var f:text;
     begin
      assign(f,'fractii.out');
      rewrite(f);
      write(f,sum);
      close(f);
     end;
     
    Procedure calc;
     var i,j:natural;
     begin
      for i:=1 to n do tab[i]:=i-1;
       for i:=2 to n do
        begin
         inc(sum,tab[i]);
         j:=i*2;
         while j<=n do begin
                        dec(tab[j],tab[i]);
                        inc(j,i);
                       end;
        end;
      sum:=sum*2+1
     end;

Begin
 Cit;
 Calc;
 Afis;
End.