-al a-a a-b a-c a-t aaa aab aac aal aat ab- aba abb abc abl abt ac- aca acb acc acl act al- ala alb alc all alt at- ata atb atc atl att baa bab bac bal bat bba bbb bbc bbl bbt bca bcb bcc bcl bct bla blb blc bll blt bta btb btc btl btt c-- caa cab cac cal cat cba cbb cbc cbl cbt cca ccb ccc ccl cct cl- cla clb clc cll clt cta ctb ctc ctl ctt la- laa lab lac lal lat lba lbb lbc lbl lbt lca lcb lcc lcl lct lla llb llc lll llt lta ltb ltc ltl ltt taa tab tac tal tat tba tbb tbc tbl tbt tca tcb tcc tcl tct tla tlc tll tlt tta ttb ttc ttl ttt