select distinct cname
from   customers
where  cno in (select cno
               from   orders
               where  ono in (select ono
                              from   odetails
                              where  pno in (select pno
                                             from   parts
                                             where  price < 20.00 and pno in
  (select pno   
   from   parts    
   where  pno in (select pno    
                  from   odetails    
                  where  pno in (select pno    
                                 from   parts    
                                 where  price < 20.00 and pno in
(select pno
from parts
where pname in (select pname
                from parts
                where pname = 'Land Before Time I'))))))));

