-er a-a a-b a-i aaa aab aad aae aai aak aao aar aas ab- aba abb abd abe abi abk abo abr abs ad- ada adb add ade adi adk ado adr ads aea aeb aed aee aei aek aeo aer aes ai- aia aib aid aie aii aik aio air ais aka akb akd ake aki akk ako akr aks aoa aob aod aoe aoi aok aoo aor aos ar- ara arb ard are ari ark aro arr ars as- asa asb asd ase asi ask aso asr ass baa bab bad bae bai bak bao bar bas bba bbb bbd bbe bbi bbk bbo bbr bbs bda bdb bdd bde bdi bdk bdo bdr bds be- bea beb bed bee bei bek beo ber bes bi- bia bib bid bie bii bik bio bir bis bka bkb bke bkk bko bkr bks boa bob bod boe boi bok boo bor bos bra brb brd bre bri brk bro brr brs bsa bsb bsd bse bsi bsk bso bsr bss daa dab dad dae dai dak dao dar das dba dbb dbd dbe dbi dbk dbo dbr dbs dda ddb ddd dde ddi ddk ddo ddr dds de- dea deb ded dee dei dek deo der des di- dia dib did die dii dik dio dir dis dka dkb dke dki dkk dko dkr dks doa dob dod doe doi dok doo dor dos dra drb drd dre dri drk dro drr drs dsa dsb dsd dse dsi dsk dso dsr dss eaa eab ead eae eai eak eao ear eas eba ebb ebd ebe ebi ebk ebo ebr ebs ed- eda edb edd ede edi edk edo edr eds eea eeb eed eee eek eeo eer ees eia eib eid eie eii eik eio eir eis eka ekb ekd eke eki eko ekr eks eo- eoa eob eod eoe eoi eok eoo eor eos era erb erd ere eri erk ero err ers es- esa esb esd ese esi esk eso esr ess i-d ia- iaa iab iad iae iai iao iar ias iba ibb ibd ibe ibi ibk ibo ibr ibs ida idb idd ide idi idk ido idr ids ie- iea ied iee iei iek ier ies iia iib iid iie iii iio iir iis ika ikb ike iki ikk iko ikr iks io- ioa iob iod ioe ioi ioo ior ios ir- ira irb ird ire iri irk iro irr irs is- isa isb isd ise isi isk iso isr iss ka- kaa kab kad kae kai kak kao kar kas kba kbb kbd kbe kbi kbk kbo kbr kbs kda kdb kde kdk kdo kdr kds ke- kea keb ked kee kei kek keo ker kes kia kib kid kie kii kik kio kir kis kkb kke kki kkk kkr kks koa kob kod koe koi kok koo kor kos kra krd kri krk kro krr krs ksa ksb ksd kse ksi ksk kso ksr kss o-i oaa oab oad oae oai oak oao oar oas ob- oba obb obd obe obi obk obo obr obs oda odb odd ode odi odo odr ods oea oeb oed oee oei oeo oer oes oia oib oid oie oii oik oio oir ois oka okb okd oke oki okk oko okr oks oo- ooa oob ood ooi ook ooo oor oos or- ora orb ord ore ori ork oro orr ors os- osa osb osd ose osi osk oso osr oss ra- raa rab rad rae rai rak rao rar ras rba rbb rbd rbe rbi rbk rbo rbr rbs rda rdb rdd rde rdi rdo rdr rds re- rea reb red ree rei rek reo rer res ria rib rid rie rii rik rio rir ris rkb rke rkk rko rks roa rob rod roe roi rok roo ror ros rra rrb rrd rri rrk rrr rrs rsa rsb rsd rse rsi rsk rso rsr rss saa sab sad sae sai sak sao sar sas sba sbb sbd sbe sbi sbk sbo sbr sbs sda sdb sdd sde sdi sdk sdo sdr sds se- sea seb sed see sei sek seo ser ses sia sib sid sie sii sik sio sir sis sk- ska skb skd ske ski skk sko skr sks soa sob sod soe soi sok soo sor sos sr- sra srb srd sre sri srk sro srr srs ss- ssa ssb ssd sse ssi ssk sso ssr sss