a-a a-b a-c aaa aab aac aad aak aan aao aar aau ab- aba abb abc abd abk abn abo abr abu ac- aca acb acc acd ack acn aco acr acu ad- ada adb adc add adk adn ado adr adu aka akb akc akd akk akn ako akr aku an- ana anb anc and ank ann ano anr anu aoa aob aoc aod aok aon aoo aor aou ar- ara arb arc ard ark arn aro arr aru au- aua aub auc aud auk aun auo aur b-u baa bab bac bad bak ban bao bar bau bba bbb bbc bbd bbk bbn bbo bbr bbu bca bcb bcc bcd bck bcn bco bcr bcu bda bdb bdc bdd bdk bdo bdr bdu bka bkb bkc bkk bkn bko bkr bna bnb bnc bnd bnk bnn bno bnr bnu boa bob boc bod bok bon boo bor bou bra brb brd brk brn bro brr bru bua bub buc bud buk bun buo bur buu c-- caa cab cac cad cak can cao car cau cba cbb cbc cbd cbk cbn cbo cbr cbu cca ccb ccc ccd cck ccn cco ccr ccu cda cdb cdc cdd cdk cdn cdo cdr cdu cka ckb ckc ckd cko cn- cna cnb cnc cnd cnn cno cnr cnu co- coa cob coc cod cok con coo cor cou cra crb crc crd crk crn cro crr cru cua cub cuc cud cuk cun cuo cur cuu daa dab dac dad dak dan dao dar dau dba dbb dbc dbd dbk dbn dbo dbr dbu dca dcb dcc dcd dck dcn dco dcr dcu dda ddb ddc ddd ddk ddn ddo ddr ddu dka dkb dkc dkk dko dkr dku dna dnb dnc dnd dnk dnn dno dnr doa dob doc dod dok don doo dor dou dra drb drc drd drk drn dro drr dru dua dub duc dud duk dun duo dur ka- kaa kab kac kad kak kan kao kar kau kba kbb kbc kbd kbk kbn kbo kbr kbu kca kcb kcc kcd kck kcn kcr kcu kda kdb kdc kdk kdo kdr kdu kkb kkc kkk kkn kkr kku kn- kna knc knd knk knn kno knr knu koa kob koc kod kok kon koo kor kou kra krc krd krk krn kro krr kru kub kuc kud kuk kun kur kuu naa nab nac nad nak nan nao nar nau nba nbb nbc nbd nbk nbn nbo nbr nbu nca ncb ncc ncd nck ncn nco ncr ncu nda ndb ndc ndd ndk ndn ndo ndr ndu nka nkc nkk nkn nko nkr nku nna nnb nnc nnk nnn nno nnu no- noa nob noc nod nok non noo nor nou nra nrb nrc nrd nrk nrn nro nrr nru nua nub nuc nud nuk nun nuo nur nuu oaa oab oac oad oak oan oao oar oau ob- oba obb obc obd obk obn obo obr obu oc- oca ocb occ ocd ock ocn oco ocr ocu oda odb odc odd odn odo odr odu oka okb okc okd okk oko okr oku on- ona onb onc ond onk onn ono onr onu oo- ooa oob ooc ood ook oon ooo oor or- ora orb orc ord ork orn oro orr oru ou- oua ouc oud ouk oun ouo our ra- raa rab rac rad rak ran rao rar rau rba rbb rbc rbd rbk rbn rbo rbr rbu rca rcb rcc rcd rcn rco rcr rcu rda rdb rdc rdd rdn rdo rdr rdu rkb rkc rkk rko rku rna rnb rnc rnd rnn rno rnr rnu roa rob roc rod rok ron roo ror rou rra rrb rrc rrd rrk rrn rrr rru rua rub ruc rud ruk run ruo rur ruu ua- uaa uab uac uad uak uan uao uar uau uba ubb ubc ubk ubn ubo ubr ubu uca ucb ucc ucd uck ucn uco ucr ucu uda udb udc udd udk udn udo udr udu uka ukb ukc ukk ukn ukr uku un- una unb unc und unk unn uno unr unu uoa uob uoc uod uok uon uoo uor ur- ura urb urc urd urk urn uro urr uru uua uuc uun uur uuu