a-a a-b a-c aaa aab aac aad aan aao aar aau ab- aba abb abc abd abn abo abr abu ac- aca acb acc acd acn aco acr acu ad- ada adb adc add adn ado adr adu an- ana anb anc and ann ano anr anu aoa aob aoc aod aon aoo aor aou ar- ara arb arc ard arn aro arr aru au- aua aub auc aud aun auo aur b-u baa bab bac bad ban bao bar bau bba bbb bbc bbd bbn bbo bbr bbu bca bcb bcc bcd bcn bco bcr bcu bda bdb bdc bdd bdo bdr bdu bna bnb bnc bnd bnn bno bnr bnu boa bob boc bod bon boo bor bou bra brb brd brn bro brr bru bua bub buc bud bun buo bur buu c-- caa cab cac cad can cao car cau cba cbb cbc cbd cbn cbo cbr cbu cca ccb ccc ccd ccn cco ccr ccu cda cdb cdc cdd cdn cdo cdr cdu cn- cna cnb cnc cnd cnn cno cnr cnu co- coa cob coc cod con coo cor cou cra crb crc crd crn cro crr cru cua cub cuc cud cun cuo cur cuu daa dab dac dad dan dao dar dau dba dbb dbc dbd dbn dbo dbr dbu dca dcb dcc dcd dcn dco dcr dcu dda ddb ddc ddd ddn ddo ddr ddu dna dnb dnc dnd dnn dno dnr doa dob doc dod don doo dor dou dra drb drc drd drn dro drr dru dua dub duc dud dun duo dur naa nab nac nad nan nao nar nau nba nbb nbc nbd nbn nbo nbr nbu nca ncb ncc ncd ncn nco ncr ncu nda ndb ndc ndd ndn ndo ndr ndu nna nnb nnc nnn nno nnu no- noa nob noc nod non noo nor nou nra nrb nrc nrd nrn nro nrr nru nua nub nuc nud nun nuo nur nuu oaa oab oac oad oan oao oar oau ob- oba obb obc obd obn obo obr obu oc- oca ocb occ ocd ocn oco ocr ocu oda odb odc odd odn odo odr odu on- ona onb onc ond onn ono onr onu oo- ooa oob ooc ood oon ooo oor or- ora orb orc ord orn oro orr oru ou- oua ouc oud oun ouo our ra- raa rab rac rad ran rao rar rau rba rbb rbc rbd rbn rbo rbr rbu rca rcb rcc rcd rcn rco rcr rcu rda rdb rdc rdd rdn rdo rdr rdu rna rnb rnc rnd rnn rno rnr rnu roa rob roc rod ron roo ror rou rra rrb rrc rrd rrn rrr rru rua rub ruc rud run ruo rur ruu ua- uaa uab uac uad uan uao uar uau uba ubb ubc ubn ubo ubr ubu uca ucb ucc ucd ucn uco ucr ucu uda udb udc udd udn udo udr udu un- una unb unc und unn uno unr unu uoa uob uoc uod uon uoo uor ur- ura urb urc urd urn uro urr uru uua uuc uun uur uuu