-er a-a a-b aaa aab aae aak aan aar aau ab- aba abb abe abk abn abr abu aea aeb aee aek aen aer aeu aka akb ake akk akn akr aku an- ana anb ane ank ann anr anu ar- ara arb are ark arn arr aru au- aua aub aue auk aun aur b-u baa bab bae bak ban bar bau bba bbb bbe bbk bbn bbr bbu be- bea beb bee bek ben ber beu bka bkb bke bkk bkn bkr bna bnb bne bnk bnn bnr bnu bra brb bre brk brn brr bru bua bub bue buk bun bur buu eaa eab eae eak ean ear eau eba ebb ebe ebk ebn ebr ebu eea eeb eee eek een eer eka ekb eke ekr eku en- ena enb ene enk enn enr enu era erb ere erk ern err eru eu- eua eub eue eun eur ka- kaa kab kae kak kan kar kau kba kbb kbe kbk kbn kbr kbu ke- kea keb kee kek ken ker kkb kke kkk kkn kkr kku kn- kna kne knk knn knr knu kra krk krn krr kru kub kue kuk kun kur kuu naa nab nae nak nan nar nau nba nbb nbe nbk nbn nbr nbu ne- nea neb nee nek nen ner neu nka nke nkk nkn nkr nku nna nnb nne nnk nnn nnu nra nrb nre nrk nrn nrr nru nua nub nue nuk nun nur nuu ra- raa rab rae rak ran rar rau rba rbb rbe rbk rbn rbr rbu re- rea reb ree rek ren rer reu rkb rke rkk rku rna rnb rnn rnr rnu rra rrb rrk rrn rrr rru rua rub rue ruk run rur ruu ua- uaa uab uae uak uan uar uau uba ubb ube ubk ubn ubr ubu uea ueb uee uen uer uka ukb uke ukk ukn ukr uku un- una unb une unk unn unr unu ur- ura urb ure urk urn urr uru uua uue uun uur uuu