-al a-a a-b a-c aaa aab aac aak aal aas ab- aba abb abc abk abl abs ac- aca acb acc ack acl acs aka akb akc akk akl aks al- ala alb alc alk all als as- asa asb asc ask asl ass baa bab bac bak bal bas bba bbb bbc bbk bbl bbs bca bcb bcc bck bcl bcs bka bkb bkc bkk bkl bks bla blb blc blk bll bls bsa bsb bsc bsk bsl bss c-- caa cab cac cak cal cas cba cbb cbc cbk cbl cbs cca ccb ccc cck ccl ccs cka ckb ckc cks cl- cla clb clc clk cll cls csa csb csc csk csl css ka- kaa kab kac kak kal kas kba kbb kbc kbk kbl kbs kca kcb kcc kck kcl kcs kkb kkc kkk kkl kks kl- kla klb klc kls ksa ksb ksc ksk ksl kss la- laa lab lac lak lal las lba lbb lbc lbk lbl lbs lca lcb lcc lck lcl lcs lka lkb lkl lks lla llb llc llk lll lls lsa lsb lsc lsk lsl lss saa sab sac sak sal sas sba sbb sbc sbk sbl sbs sca scb scc sck scl scs sk- ska skb skc skk skl sks sla slb slc slk sll sls ss- ssa ssb ssc ssk ssl sss