bbb bbd bbn bbo bbt bdb bdd bdo bdt bnb bnd bnn bno bnt bob bod bon boo bot btb btd btn bto btt dbb dbd dbn dbo dbt ddb ddd ddn ddo ddt dnb dnd dnn dno dnt dob dod don doo dot dtb dtd dtn dto dtt nbb nbd nbn nbo nbt ndb ndd ndn ndo ndt nnb nnn nno nnt no- nob nod non noo not ntb ntd ntn nto ntt ob- obb obd obn obo obt odb odd odn odo odt on- onb ond onn ono ont oo- oob ood oon ooo oot ot- otb otd otn oto ott tbb tbd tbn tbo tbt tdb tdd tdn tdo tdt tnb tnd tnn tno tnt to- tob tod ton too tot ttb ttd ttn tto ttt