program Zadacha;

{$APPTYPE CONSOLE}

uses
  SysUtils;
 var i,j,n,k:integer;
 f1,f2:text;
begin
  { TODO -oUser -cConsole Main : Insert code here }
 assign(f1,'pair.in');
 assign(f2,'pair.out');
 reset(f1);
 rewrite(f2);
 read(f1,n);
 k:=0;
 for i:=1 to n do
 begin
  for j:=1 to i div 2 do
  begin
   if i mod j =0 then inc(k);
  end;
  inc(k);
 end;
 writeln(f2,k);
 close(f1);
 close(f2);
end.