a-a a-b aaa aab aaj aak aao aas ab- aba abb abj abk abo abs aja ajb ajj ajk ajo ajs aka akb akj akk ako aks aoa aob aoj aok aoo aos as- asa asb asj ask aso ass baa bab baj bak bao bas bba bbb bbk bbo bbs bja bjj bjk bjs bka bkb bkk bko bks boa bob boj bok boo bos bsa bsb bsj bsk bso bss jaa jab jaj jak jao jas jba jbj jbk jbo jbs jja jjb jjj jjk jjs jka jkb jkk jko jks joa job joj jok joo jos jsa jsb jsj jsk jso jss ka- kaa kab kaj kak kao kas kba kbb kbk kbo kbs kjb kjs kkb kkk kks koa kob kok koo kos ksa ksb ksk kso kss oaa oab oaj oak oao oas ob- oba obb obj obk obo obs oja ojb ojo ojs oka okb okj okk oko oks oo- ooa oob ook ooo oos os- osa osb osj osk oso oss saa sab saj sak sao sas sba sbb sbj sbk sbo sbs sja sjb sjj sjk sjs sk- ska skb skj skk sko sks soa sob soj sok soo sos ss- ssa ssb ssj ssk sso sss