-al a-a a-b a-c aaa aab aac aal aan ab- aba abb abc abl abn ac- aca acb acc acl acn al- ala alb alc all aln an- ana anb anc anl ann baa bab bac bal ban bba bbb bbc bbl bbn bca bcb bcc bcl bcn bla blb blc bll bln bna bnb bnc bnl bnn c-- caa cab cac cal can cba cbb cbc cbl cbn cca ccb ccc ccl ccn cl- cla clb clc cll cln cn- cna cnb cnc cnl cnn la- laa lab lac lal lan lba lbb lbc lbl lca lcb lcc lcl lcn lla llb llc lll lln lna lnb lnc lnl lnn naa nab nac nal nan nba nbb nbc nbl nbn nca ncb ncc ncl ncn nla nlb nlc nll nln nna nnb nnc nnl nnn