a-a a-b a-c aaa aab aac aaj aak aan aao aas ab- aba abb abc abj abk abn abo abs ac- aca acb acc acj ack acn aco acs aja ajb ajc ajj ajk ajn ajo ajs aka akb akc akj akk akn ako aks an- ana anb anc anj ank ann ano ans aoa aob aoc aoj aok aon aoo aos as- asa asb asc asj ask asn aso ass baa bab bac baj bak ban bao bas bba bbb bbc bbk bbn bbo bbs bca bcb bcc bcj bck bcn bco bcs bja bjc bjj bjk bjn bjs bka bkb bkc bkk bkn bko bks bna bnb bnc bnj bnk bnn bno bns boa bob boc boj bok bon boo bos bsa bsb bsc bsj bsk bsn bso bss c-- c-j caa cab cac caj cak can cao cas cba cbb cbc cbj cbk cbn cbo cbs cca ccb ccc ccj cck ccn cco ccs cja cjb cjc cjk cjs cka ckb ckc cko cks cn- cna cnb cnc cnj cnn cno cns co- coa cob coc coj cok con coo cos csa csb csc csj csk csn cso css jaa jab jac jaj jak jan jao jas jba jbc jbj jbk jbo jbs jca jcb jcc jck jco jcs jja jjb jjc jjj jjk jjs jka jkb jkk jkn jko jks jna jnc jnj jnn jno jns joa job joc joj jok jon joo jos jsa jsb jsc jsj jsk jsn jso jss ka- kaa kab kac kaj kak kan kao kas kba kbb kbc kbk kbn kbo kbs kca kcb kcc kck kcn kcs kjb kjc kjs kkb kkc kkk kkn kks kn- kna knc knk knn kno koa kob koc kok kon koo kos ksa ksb ksc ksk ksn kso kss naa nab nac naj nak nan nao nas nba nbb nbc nbk nbn nbo nbs nca ncb ncc nck ncn nco ncs nja njc njk njn njs nka nkc nkj nkk nkn nko nks nna nnb nnc nnk nnn nno nns no- noa nob noc noj nok non noo nos nsa nsb nsc nsk nsn nso nss oaa oab oac oaj oak oan oao oas ob- oba obb obc obj obk obn obo obs oc- oca ocb occ ocj ock ocn oco ocs oja ojb ojc ojo ojs oka okb okc okj okk oko oks on- ona onb onc onj onk onn ono ons oo- ooa oob ooc ook oon ooo oos os- osa osb osc osj osk osn oso oss saa sab sac saj sak san sao sas sba sbb sbc sbj sbk sbn sbo sbs sca scb scc scj sck scn sco scs sja sjb sjc sjj sjk sjs sk- ska skb skc skj skk sko sks sna snb snc snj snk snn sno sns soa sob soc soj sok son soo sos ss- ssa ssb ssc ssj ssk ssn sso sss