program infoarena002;
   var  i,n,j,nr:integer;
     a:array[1..maxint] of longint;
     fin,fou:text;
Begin
 assign(fin,'fractii.in');
 assign(fou,'fractii.out');
  reset(fin);
  rewrite(fou);
 readln(fin,n);
  for i:=1 to n do a[i]:=i-1;

  for i:=2 to n do
  begin
   j:=i+i;
   repeat

    a[j]:=a[j]-a[i];
    j:=j+i;

   until j>=n;
  end;
  for i:=2 to n do
   nr:=nr+a[i];

  write(fou,nr*2+1);
  close(fin); close(fou);
End.