-al a-a a-b a-c a-t aaa aab aac aal aas aat ab- aba abb abc abl abs abt ac- aca acb acc acl acs act al- ala alb alc all als alt as- asa asb asc asl ass ast at- ata atb atc atl ats att baa bab bac bal bas bat bba bbb bbc bbl bbs bbt bca bcb bcc bcl bcs bct bla blb blc bll bls blt bsa bsb bsc bsl bss bst bta btb btc btl bts btt c-- caa cab cac cal cas cat cba cbb cbc cbl cbs cbt cca ccb ccc ccl ccs cct cl- cla clb clc cll cls clt csa csb csc csl css cst cta ctb ctc ctl cts ctt la- laa lab lac lal las lat lba lbb lbc lbl lbs lbt lca lcb lcc lcl lcs lct lla llb llc lll lls llt lsa lsb lsc lsl lss lst lta ltb ltc ltl lts ltt saa sab sac sal sas sat sba sbb sbc sbl sbs sbt sca scb scc scl scs sct sla slb slc sll sls slt ss- ssa ssb ssc ssl sss sst sta stb stc stl sts stt taa tab tac tal tas tat tba tbb tbc tbl tbs tbt tca tcb tcc tcl tcs tct tla tlc tll tls tlt tsa tsb tsc tsl tss tst tta ttb ttc ttl tts ttt