a-a a-b a-c aaa aab aac aah aak aas ab- aba abb abc abh abk abs ac- aca acb acc ach ack acs aha ahb ahc ahh ahk ahs aka akb akc akh akk aks as- asa asb asc ash ask ass baa bab bac bah bak bas bba bbb bbc bbh bbk bbs bca bcb bcc bch bck bcs bha bhb bhc bhh bhk bhs bka bkb bkc bkk bks bsa bsb bsc bsh bsk bss c-- caa cab cac cah cak cas cba cbb cbc cbh cbk cbs cca ccb ccc cch cck ccs ch- cha chb chc chh chk chs cka ckb ckc ckh cks csa csb csc csh csk css haa hab hac hah hak has hba hbb hbc hbh hbk hbs hca hcb hcc hch hck hcs hha hhb hhc hhh hhk hhs hka hkb hkh hkk hks hsa hsb hsc hsh hsk hss ka- kaa kab kac kah kak kas kba kbb kbc kbh kbk kbs kca kcb kcc kch kck kcs kha khh khk khs kkb kkc kkh kkk kks ksa ksb ksc ksh ksk kss saa sab sac sah sak sas sba sbb sbc sbh sbk sbs sca scb scc sch sck scs sh- sha shb shc shh shk shs sk- ska skb skc skh skk sks ss- ssa ssb ssc ssh ssk sss