-al a-a a-b a-c aaa aab aac aak aal aan ab- aba abb abc abk abl abn ac- aca acb acc ack acl acn aka akb akc akk akl akn al- ala alb alc alk all aln an- ana anb anc ank anl ann baa bab bac bak bal ban bba bbb bbc bbk bbl bbn bca bcb bcc bck bcl bcn bka bkb bkc bkk bkl bkn bla blb blc blk bll bln bna bnb bnc bnk bnl bnn c-- caa cab cac cak cal can cba cbb cbc cbk cbl cbn cca ccb ccc cck ccl ccn cka ckb ckc cl- cla clb clc clk cll cln cn- cna cnb cnc cnl cnn ka- kaa kab kac kak kal kan kba kbb kbc kbk kbl kbn kca kcb kcc kck kcl kcn kkb kkc kkk kkl kkn kl- kla klb klc kn- kna knc knk knl knn la- laa lab lac lak lal lan lba lbb lbc lbk lbl lca lcb lcc lck lcl lcn lka lkb lkl lla llb llc llk lll lln lna lnb lnc lnk lnl lnn naa nab nac nak nal nan nba nbb nbc nbk nbl nbn nca ncb ncc nck ncl ncn nka nkc nkk nkn nla nlb nlc nlk nll nln nna nnb nnc nnk nnl nnn