a-a a-b a-c a-q aaa aab aac aak aaq aas ab- aba abb abc abk abq abs ac- aca acb acc ack acq acs aka akb akc akk aks aqa aqc aqs as- asa asb asc ask asq ass baa bab bac bak baq bas bba bbb bbc bbk bbq bbs bca bcb bcc bck bcq bcs bka bkb bkc bkk bkq bks bqc bsa bsb bsc bsk bss c-- caa cab cac cak caq cas cba cbb cbc cbk cbq cbs cca ccb ccc cck ccs cka ckb ckc cks cqa cqb cqc cqs csa csb csc csk csq css ka- kaa kab kac kak kas kba kbb kbc kbk kbs kca kcb kcc kck kcs kkb kkc kkk kks kqa ksa ksb ksc ksk kss qaa qac qas qba qbc qbq qbs qca qcc qcs qqk qqq qsa qsc saa sab sac sak saq sas sba sbb sbc sbk sbq sbs sca scb scc sck scs sk- ska skb skc skk skq sks sqa sqq sqs ss- ssa ssb ssc ssk ssq sss