var f,g:text;
    i,j,n,q:longint;
    r:longint;
begin
 assign(f,'fractii.in');
 assign(g,'fractii.out');
 reset(f);
 rewrite(g);
 readln(f,n);
 close(f);


 for i:=1 to n do
  for j:=i to n do begin
   if (i mod j <> 0) and (j mod i <> 0 ) then
    r:=r+2;
   if (i=1) or (j=1) then inc(r);
 end;
{r:=r+n*2;   }
  writeln(g,r+n-1);
 close(g);
end.