-al a-a a-b a-c a-t aaa aab aac aal aan aat ab- aba abb abc abl abn abt ac- aca acb acc acl acn act al- ala alb alc all aln alt an- ana anb anc anl ann ant at- ata atb atc atl atn att baa bab bac bal ban bat bba bbb bbc bbl bbn bbt bca bcb bcc bcl bcn bct bla blb blc bll bln blt bna bnb bnc bnl bnn bnt bta btb btc btl btn btt c-- caa cab cac cal can cat cba cbb cbc cbl cbn cbt cca ccb ccc ccl ccn cct cl- cla clb clc cll cln clt cn- cna cnb cnc cnl cnn cnt cta ctb ctc ctl ctn ctt la- laa lab lac lal lan lat lba lbb lbc lbl lbt lca lcb lcc lcl lcn lct lla llb llc lll lln llt lna lnb lnc lnl lnn lnt lta ltb ltc ltl ltt naa nab nac nal nan nat nba nbb nbc nbl nbn nbt nca ncb ncc ncl ncn nct nla nlb nlc nll nln nlt nna nnb nnc nnl nnn nnt nta ntb ntc ntn ntt taa tab tac tal tan tat tba tbb tbc tbl tbn tbt tca tcb tcc tcl tcn tct tla tlc tll tln tlt tna tnb tnc tnl tnn tnt tta ttb ttc ttl ttn ttt