-er a-a a-b a-c aaa aab aac aae aan aar aau ab- aba abb abc abe abn abr abu ac- aca acb acc ace acn acr acu aea aeb aec aee aen aer aeu an- ana anb anc ane ann anr anu ar- ara arb arc are arn arr aru au- aua aub auc aue aun aur b-u baa bab bac bae ban bar bau bba bbb bbc bbe bbn bbr bbu bca bcb bcc bce bcn bcr bcu be- bea beb bec bee ben ber beu bna bnb bnc bne bnn bnr bnu bra brb bre brn brr bru bua bub buc bue bun bur buu c-- caa cab cac cae can car cau cba cbb cbc cbe cbn cbr cbu cca ccb ccc cce ccn ccr ccu ce- cea ceb cec cee cen cer ceu cn- cna cnb cnc cne cnn cnr cnu cra crb crc cre crn crr cru cua cub cuc cue cun cur cuu eaa eab eac eae ean ear eau eba ebb ebc ebe ebn ebr ebu ec- eca ecb ecc ece ecn ecr ecu eea eeb eec eee een eer en- ena enb enc ene enn enr enu era erb erc ere ern err eru eu- eua eub euc eue eun eur naa nab nac nae nan nar nau nba nbb nbc nbe nbn nbr nbu nca ncb ncc nce ncn ncr ncu ne- nea neb nec nee nen ner neu nna nnb nnc nne nnn nnu nra nrb nrc nre nrn nrr nru nua nub nuc nue nun nur nuu ra- raa rab rac rae ran rar rau rba rbb rbc rbe rbn rbr rbu rca rcb rcc rce rcn rcr rcu re- rea reb rec ree ren rer reu rna rnb rnc rnn rnr rnu rra rrb rrc rrn rrr rru rua rub ruc rue run rur ruu ua- uaa uab uac uae uan uar uau uba ubb ubc ube ubn ubr ubu uca ucb ucc uce ucn ucr ucu uea ueb uec uee uen uer un- una unb unc une unn unr unu ur- ura urb urc ure urn urr uru uua uuc uue uun uur uuu