-er a-a a-b a-i aaa aab aae aai aar aas aau aax ab- aba abb abe abi abr abs abu abx aea aeb aee aei aer aes aeu aex ai- aia aib aie aii air ais aiu aix ar- ara arb are ari arr ars aru arx as- asa asb ase asi asr ass asu asx au- aua aub aue aui aur aus aux ax- axa axe axi axr axs axx b-u baa bab bae bai bar bas bau bax bba bbb bbe bbi bbr bbs bbu bbx be- bea beb bee bei ber bes beu bex bi- bia bib bie bii bir bis biu bix bra brb bre bri brr brs bru brx bsa bsb bse bsi bsr bss bsu bsx bua bub bue bui bur bus buu bux bxb bxi bxx eaa eab eae eai ear eas eau eax eba ebb ebe ebi ebr ebs ebu ebx eea eeb eee eer ees eex eia eib eie eii eir eis eiu eix era erb ere eri err ers eru es- esa esb ese esi esr ess esu esx eu- eua eub eue eui eur eus eux ex- exa exe exi exr exs exu exx ia- iaa iab iae iai iar ias iau iba ibb ibe ibi ibr ibs ibu ibx ie- iea iee iei ier ies iex iia iib iie iii iir iis iiu iix ir- ira irb ire iri irr irs iru irx is- isa isb ise isi isr iss isu iu- iua iub iue iui iur ius ixe ixi ra- raa rab rae rai rar ras rau rax rba rbb rbe rbi rbr rbs rbu rbx re- rea reb ree rei rer res reu rex ria rib rie rii rir ris rix rra rrb rri rrr rrs rru rsa rsb rse rsi rsr rss rsu rsx rua rub rue rui rur rus ruu rux rxr rxs saa sab sae sai sar sas sau sax sba sbb sbe sbi sbr sbs sbu sbx se- sea seb see sei ser ses seu sex sia sib sie sii sir sis siu six sr- sra srb sre sri srr srs srx ss- ssa ssb sse ssi ssr sss ssu ssx sua sub sue sui sur sus suu sux sxi sxs sxu ua- uaa uab uae uai uar uas uau uba ubb ube ubi ubr ubs ubu ubx uea ueb uee uei uer ues uia uib uie uii uir uis uiu ur- ura urb ure uri urr urs uru urx usa usb use usi usr uss usu usx uua uue uur uus uuu uxb uxr uxu xaa xar xas xau xbe xbr xbx xee xer xes xeu xex xia xie xii xis xiu xix xrx xsa xsb xsi xss xue xui xus xxi xxx