a-a a-b a-t aaa aab aad aan aao aat ab- aba abb abd abn abo abt ad- ada adb add adn ado adt an- ana anb and ann ano ant aoa aob aod aon aoo aot at- ata atb atd atn ato att baa bab bad ban bao bat bba bbb bbd bbn bbo bbt bda bdb bdd bdo bdt bna bnb bnd bnn bno bnt boa bob bod bon boo bot bta btb btd btn bto btt daa dab dad dan dao dat dba dbb dbd dbn dbo dbt dda ddb ddd ddn ddo ddt dna dnb dnd dnn dno dnt doa dob dod don doo dot dta dtb dtd dtn dto dtt naa nab nad nan nao nat nba nbb nbd nbn nbo nbt nda ndb ndd ndn ndo ndt nna nnb nnn nno nnt no- noa nob nod non noo not nta ntb ntd ntn nto ntt oaa oab oad oan oao oat ob- oba obb obd obn obo obt oda odb odd odn odo odt on- ona onb ond onn ono ont oo- ooa oob ood oon ooo oot ot- ota otb otd otn oto ott taa tab tad tan tao tat tba tbb tbd tbn tbo tbt tda tdb tdd tdn tdo tdt tna tnb tnd tnn tno tnt to- toa tob tod ton too tot tta ttb ttd ttn tto ttt