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