a-a a-b a-c aaa aab aac aaj aak aao aar aas ab- aba abb abc abj abk abo abr abs ac- aca acb acc acj ack aco acr acs aja ajb ajc ajj ajk ajo ajr ajs aka akb akc akj akk ako akr aks aoa aob aoc aoj aok aoo aor aos ar- ara arb arc arj ark aro arr ars as- asa asb asc asj ask aso asr ass baa bab bac baj bak bao bar bas bba bbb bbc bbk bbo bbr bbs bca bcb bcc bcj bck bco bcr bcs bja bjc bjj bjk bjr bjs bka bkb bkc bkk bko bkr bks boa bob boc boj bok boo bor bos bra brb brj brk bro brr brs bsa bsb bsc bsj bsk bso bsr bss c-- c-j caa cab cac caj cak cao car cas cba cbb cbc cbj cbk cbo cbr cbs cca ccb ccc ccj cck cco ccr ccs cja cjb cjc cjk cjr cjs cka ckb ckc cko cks co- coa cob coc coj cok coo cor cos cra crb crc crj crk cro crr crs csa csb csc csj csk cso csr css jaa jab jac jaj jak jao jar jas jba jbc jbj jbk jbo jbr jbs jca jcb jcc jck jco jcr jcs jja jjb jjc jjj jjk jjr jjs jka jkb jkk jko jkr jks joa job joc joj jok joo jor jos jra jrb jrc jrk jro jrr jrs jsa jsb jsc jsj jsk jso jsr jss ka- kaa kab kac kaj kak kao kar kas kba kbb kbc kbk kbo kbr kbs kca kcb kcc kck kcr kcs kjb kjc kjr kjs kkb kkc kkk kkr kks koa kob koc kok koo kor kos kra krc krk kro krr krs ksa ksb ksc ksk kso ksr kss oaa oab oac oaj oak oao oar oas ob- oba obb obc obj obk obo obr obs oc- oca ocb occ ocj ock oco ocr ocs oja ojb ojc ojo ojs oka okb okc okj okk oko okr oks oo- ooa oob ooc ook ooo oor oos or- ora orb orc ork oro orr ors os- osa osb osc osj osk oso osr oss ra- raa rab rac raj rak rao rar ras rba rbb rbc rbk rbo rbr rbs rca rcb rcc rcj rco rcr rcs rja rjc rjk rjr rkb rkc rkk rko rks roa rob roc roj rok roo ror ros rra rrb rrc rrk rrr rrs rsa rsb rsc rsj rsk rso rsr rss saa sab sac saj sak sao sar sas sba sbb sbc sbj sbk sbo sbr sbs sca scb scc scj sck sco scr scs sja sjb sjc sjj sjk sjr sjs sk- ska skb skc skj skk sko skr sks soa sob soc soj sok soo sor sos sr- sra srb src srj srk sro srr srs ss- ssa ssb ssc ssj ssk sso ssr sss