-er a-a a-b aaa aab aae aaj aak aao aar aas ab- aba abb abe abj abk abo abr abs aea aeb aee aej aek aeo aer aes aja ajb aje ajj ajk ajo ajr ajs aka akb ake akj akk ako akr aks aoa aob aoe aoj aok aoo aor aos ar- ara arb are arj ark aro arr ars as- asa asb ase asj ask aso asr ass baa bab bae baj bak bao bar bas bba bbb bbe bbk bbo bbr bbs be- bea beb bee bek beo ber bes bja bjj bjk bjr bjs bka bkb bke bkk bko bkr bks boa bob boe boj bok boo bor bos bra brb bre brj brk bro brr brs bsa bsb bse bsj bsk bso bsr bss eaa eab eae eaj eak eao ear eas eba ebb ebe ebj ebk ebo ebr ebs eea eeb eee eek eeo eer ees eja ejo eka ekb eke eko ekr eks eo- eoa eob eoe eok eoo eor eos era erb ere erk ero err ers es- esa esb ese esk eso esr ess jaa jab jae jaj jak jao jar jas jba jbj jbk jbo jbr jbs jea jeb jee jej jek jeo jer jes jja jjb jjj jjk jjr jjs jka jkb jkk jko jkr jks joa job joe joj jok joo jor jos jra jrb jrk jro jrr jrs jsa jsb jse jsj jsk jso jsr jss ka- kaa kab kae kaj kak kao kar kas kba kbb kbe kbk kbo kbr kbs ke- kea keb kee kek keo ker kes kjb kje kjr kjs kkb kke kkk kkr kks koa kob koe kok koo kor kos kra krk kro krr krs ksa ksb kse ksk kso ksr kss oaa oab oae oaj oak oao oar oas ob- oba obb obe obj obk obo obr obs oea oeb oee oeo oer oes oja ojb oje ojo ojs oka okb oke okj okk oko okr oks oo- ooa oob ook ooo oor oos or- ora orb ore ork oro orr ors os- osa osb ose osj osk oso osr oss ra- raa rab rae raj rak rao rar ras rba rbb rbe rbk rbo rbr rbs re- rea reb ree rek reo rer res rja rjk rjr rkb rke rkk rko rks roa rob roe roj rok roo ror ros rra rrb rrk rrr rrs rsa rsb rse rsj rsk rso rsr rss saa sab sae saj sak sao sar sas sba sbb sbe sbj sbk sbo sbr sbs se- sea seb see sej sek seo ser ses sja sjb sje sjj sjk sjr sjs sk- ska skb ske skj skk sko skr sks soa sob soe soj sok soo sor sos sr- sra srb sre srj srk sro srr srs ss- ssa ssb sse ssj ssk sso ssr sss