-er a-a a-b a-c aaa aab aac aae aan aar aas aau aax ab- aba abb abc abe abn abr abs abu abx ac- aca acb acc ace acn acr acs acu acx aea aeb aec aee aen aer aes aeu aex an- ana anb anc ane ann anr ans anu anx ar- ara arb arc are arn arr ars aru arx as- asa asb asc ase asn asr ass asu asx au- aua aub auc aue aun aur aus aux ax- axa axe axn axr axs axx b-u baa bab bac bae ban bar bas bau bax bba bbb bbc bbe bbn bbr bbs bbu bbx bca bcb bcc bce bcn bcr bcs bcu bcx be- bea beb bec bee ben ber bes beu bex bna bnb bnc bne bnn bnr bns bnu bnx bra brb bre brn brr brs bru brx bsa bsb bsc bse bsn bsr bss bsu bsx bua bub buc bue bun bur bus buu bux bxb bxn bxx c-- caa cab cac cae can car cas cau cax cba cbb cbc cbe cbn cbr cbs cbu cbx cca ccb ccc cce ccn ccr ccs ccu ccx ce- cea ceb cec cee cen cer ces ceu cex cn- cna cnb cnc cne cnn cnr cns cnu cnx cra crb crc cre crn crr crs cru crx csa csb csc cse csn csr css csu csx cua cub cuc cue cun cur cus cuu cxc cxr cxs cxx eaa eab eac eae ean ear eas eau eax eba ebb ebc ebe ebn ebr ebs ebu ebx ec- eca ecb ecc ece ecn ecr ecs ecu ecx eea eeb eec eee een eer ees eex en- ena enb enc ene enn enr ens enu era erb erc ere ern err ers eru es- esa esb esc ese esn esr ess esu esx eu- eua eub euc eue eun eur eus eux ex- exa exc exe exr exs exu exx naa nab nac nae nan nar nas nau nax nba nbb nbc nbe nbn nbr nbs nbu nbx nca ncb ncc nce ncn ncr ncs ncu ncx ne- nea neb nec nee nen ner nes neu nex nna nnb nnc nne nnn nns nnu nra nrb nrc nre nrn nrr nrs nru nrx nsa nsb nsc nse nsn nsr nss nsu nsx nua nub nuc nue nun nur nus nuu nux nxc ra- raa rab rac rae ran rar ras rau rax rba rbb rbc rbe rbn rbr rbs rbu rbx rca rcb rcc rce rcn rcr rcs rcu rcx re- rea reb rec ree ren rer res reu rex rna rnb rnc rnn rnr rns rnu rra rrb rrc rrn rrr rrs rru rsa rsb rsc rse rsn rsr rss rsu rsx rua rub ruc rue run rur rus ruu rux rxr rxs saa sab sac sae san sar sas sau sax sba sbb sbc sbe sbn sbr sbs sbu sbx sca scb scc sce scn scr scs scu scx se- sea seb sec see sen ser ses seu sex sna snb snc sne snn snr sns snu sr- sra srb src sre srn srr srs srx ss- ssa ssb ssc sse ssn ssr sss ssu ssx sua sub suc sue sun sur sus suu sux sxc sxn sxs sxu ua- uaa uab uac uae uan uar uas uau uba ubb ubc ube ubn ubr ubs ubu ubx uca ucb ucc uce ucn ucr ucs ucu uea ueb uec uee uen uer ues un- una unb unc une unn unr uns unu unx ur- ura urb urc ure urn urr urs uru urx usa usb usc use usn usr uss usu usx uua uuc uue uun uur uus uuu uxb uxc uxr uxu xaa xac xan xar xas xau xbc xbe xbr xbx xcb xcr xcx xee xen xer xes xeu xex xna xnc xns xnu xrc xrx xsa xsb xsc xss xue xun xus xxx