bbb bbk bbn bbo bbt bkb bkk bkn bko bkt bnb bnk bnn bno bnt bob bok bon boo bot btb btk btn bto btt k-t kbb kbk kbn kbo kkb kkk kkn kkt kn- knk knn kno knt kob kok kon koo kot ktb ktk ktn kto ktt nbb nbk nbn nbo nbt nkk nkn nko nkt nnb nnk nnn nno nnt no- nob nok non noo not ntb ntk ntn nto ntt ob- obb obk obn obo obt okb okk oko on- onb onk onn ono ont oo- oob ook oon ooo oot ot- otb otk otn oto ott tbb tbk tbn tbo tbt tkb tkk tko tkt tnb tnk tnn tno tnt to- tob tok ton too tot ttb ttk ttn tto ttt