bbbb bobb bobo bobu bokn boko boku bonk bonn bono bonu boob book boon bouk boun bubb bubo bubu bukk buko buku bunb bunk bunn buno bunu buon kbbb kbbk kbbo kbbu kbkb kbkk kbko kbnn kbno kbnu kbob kbok kbon kboo kbub kbuk kbun kbuu kkbb kkbn kkbo kkkk kknb kknn kkno kknu kkob kkon kkoo kkuu knbb knbn knbu knkk knnb knnk knob knok knon knou knub knuk kobb kobk kobn kobo kobu kokb kokk kokn koko koku konk kono koob kook koon kooo koou koub kouu kubb kubo kubu kukk kukn kuku kunk kuno kunu kuok kuon kuoo kuub kuuk kuuu nbbo nkok nnnn nobo nobu noko non- nonn nono nonu noo- noob nook noon nooo noun nubk nuku nunk nunn nuno nuon nuuk obbo obkb obok obon okko okno okok okon okun onno onon ooku oooo oun- ouu- ubbo ubon ukko ukok ukon unkn unko unno unon uuno uuuu