a-a a-b a-c aaa aab aac aad aan aao aau ab- aba abb abc abd abn abo abu ac- aca acb acc acd acn aco acu ad- ada adb adc add adn ado adu an- ana anb anc and ann ano anu aoa aob aoc aod aon aoo aou au- aua aub auc aud aun auo b-u baa bab bac bad ban bao bau bba bbb bbc bbd bbn bbo bbu bca bcb bcc bcd bcn bco bcu bda bdb bdc bdd bdo bdu bna bnb bnc bnd bnn bno bnu boa bob boc bod bon boo bou bua bub buc bud bun buo buu c-- caa cab cac cad can cao cau cba cbb cbc cbd cbn cbo cbu cca ccb ccc ccd ccn cco ccu cda cdb cdc cdd cdn cdo cdu cn- cna cnb cnc cnd cnn cno cnu co- coa cob coc cod con coo cou cua cub cuc cud cun cuo cuu daa dab dac dad dan dao dau dba dbb dbc dbd dbn dbo dbu dca dcb dcc dcd dcn dco dcu dda ddb ddc ddd ddn ddo ddu dna dnb dnc dnd dnn dno doa dob doc dod don doo dou dua dub duc dud dun duo naa nab nac nad nan nao nau nba nbb nbc nbd nbn nbo nbu nca ncb ncc ncd ncn nco ncu nda ndb ndc ndd ndn ndo ndu nna nnb nnc nnn nno nnu no- noa nob noc nod non noo nou nua nub nuc nud nun nuo nuu oaa oab oac oad oan oao oau ob- oba obb obc obd obn obo obu oc- oca ocb occ ocd ocn oco ocu oda odb odc odd odn odo odu on- ona onb onc ond onn ono onu oo- ooa oob ooc ood oon ooo ou- oua ouc oud oun ouo ua- uaa uab uac uad uan uao uau uba ubb ubc ubn ubo ubu uca ucb ucc ucd ucn uco ucu uda udb udc udd udn udo udu un- una unb unc und unn uno unu uoa uob uoc uod uon uoo uua uuc uun uuu