-er a-a a-b aaa aab aae aan aar aas aau aax ab- aba abb abe abn abr abs abu abx aea aeb aee aen aer aes aeu aex an- ana anb ane ann anr ans anu anx ar- ara arb are arn arr ars aru arx as- asa asb ase asn asr ass asu asx au- aua aub aue aun aur aus aux ax- axa axe axn axr axs axx b-u baa bab bae ban bar bas bau bax bba bbb bbe bbn bbr bbs bbu bbx be- bea beb bee ben ber bes beu bex bna bnb bne bnn bnr bns bnu bnx bra brb bre brn brr brs bru brx bsa bsb bse bsn bsr bss bsu bsx bua bub bue bun bur bus buu bux bxb bxn bxx eaa eab eae ean ear eas eau eax eba ebb ebe ebn ebr ebs ebu ebx eea eeb eee een eer ees eex en- ena enb ene enn enr ens enu era erb ere ern err ers eru es- esa esb ese esn esr ess esu esx eu- eua eub eue eun eur eus eux ex- exa exe exr exs exu exx naa nab nae nan nar nas nau nax nba nbb nbe nbn nbr nbs nbu nbx ne- nea neb nee nen ner nes neu nex nna nnb nne nnn nns nnu nra nrb nre nrn nrr nrs nru nrx nsa nsb nse nsn nsr nss nsu nsx nua nub nue nun nur nus nuu nux ra- raa rab rae ran rar ras rau rax rba rbb rbe rbn rbr rbs rbu rbx re- rea reb ree ren rer res reu rex rna rnb rnn rnr rns rnu rra rrb rrn rrr rrs rru rsa rsb rse rsn rsr rss rsu rsx rua rub rue run rur rus ruu rux rxr rxs saa sab sae san sar sas sau sax sba sbb sbe sbn sbr sbs sbu sbx se- sea seb see sen ser ses seu sex sna snb sne snn snr sns snu sr- sra srb sre srn srr srs srx ss- ssa ssb sse ssn ssr sss ssu ssx sua sub sue sun sur sus suu sux sxn sxs sxu ua- uaa uab uae uan uar uas uau uba ubb ube ubn ubr ubs ubu ubx uea ueb uee uen uer ues un- una unb une unn unr uns unu unx ur- ura urb ure urn urr urs uru urx usa usb use usn usr uss usu usx uua uue uun uur uus uuu uxb uxr uxu xaa xan xar xas xau xbe xbr xbx xee xen xer xes xeu xex xna xns xnu xrx xsa xsb xss xue xun xus xxx