-er a-a a-b aaa aab aae aak aan aar aau aav ab- aba abb abe abk abn abr abu abv aea aeb aee aek aen aer aeu aev aka akb ake akk akn akr aku akv an- ana anb ane ank ann anr anu anv ar- ara arb are ark arn arr aru arv au- aua aub aue auk aun aur auv av- ava avb ave avk avn avr avu b-u baa bab bae bak ban bar bau bav bba bbb bbe bbk bbn bbr bbu be- bea beb bee bek ben ber beu bev bka bkb bke bkk bkn bkr bkv bna bnb bne bnk bnn bnr bnu bnv bra brb bre brk brn brr bru brv bua bub bue buk bun bur buu bva bvb bve bvk bvn bvr bvu bvv eaa eab eae eak ean ear eau eav eba ebb ebe ebk ebn ebr ebu ebv eea eeb eee eek een eer eev eka ekb eke ekr eku ekv en- ena enb ene enk enn enr enu env era erb ere erk ern err eru erv eu- eua eub eue eun eur euv eva evb eve evn evr evv ka- kaa kab kae kak kan kar kau kav kba kbb kbe kbk kbn kbr kbu ke- kea keb kee kek ken ker kev kkb kke kkk kkn kkr kku kkv kn- kna kne knk knn knr knu kra krk krn krr kru krv kub kue kuk kun kur kuu kva kvb kvk kvn kvr kvv naa nab nae nak nan nar nau nav nba nbb nbe nbk nbn nbr nbu nbv ne- nea neb nee nek nen ner neu nev nka nke nkk nkn nkr nku nna nnb nne nnk nnn nnu nnv nra nrb nre nrk nrn nrr nru nrv nua nub nue nuk nun nur nuu nuv nva nvb nve nvk nvn nvu nvv ra- raa rab rae rak ran rar rau rav rba rbb rbe rbk rbn rbr rbu re- rea reb ree rek ren rer reu rev rkb rke rkk rku rkv rna rnb rnn rnr rnu rnv rra rrb rrk rrn rrr rru rua rub rue ruk run rur ruu ruv rva rvb rve rvn rvr rvu rvv ua- uaa uab uae uak uan uar uau uav uba ubb ube ubk ubn ubr ubu ubv uea ueb uee uen uer uka ukb uke ukk ukn ukr uku un- una unb une unk unn unr unu unv ur- ura urb ure urk urn urr uru uua uue uun uur uuu uva uvb uve uvu uvv v-a v-e vaa vab vae vak van var vau vav vba vbk vbr vbv vea veb vee vek ven ver veu vka vkb vn- vna vnr vnu vnv vra vrb vre vrk vrn vrr vru vue vuk vur vuv vva vvb vvr vvv