-al a-a a-b a-t aaa aab aad aal aat ab- aba abb abd abl abt ad- ada adb add adl adt al- ala alb ald all alt at- ata atb atd atl att baa bab bad bal bat bba bbb bbd bbl bbt bda bdb bdd bdl bdt bla blb bld bll blt bta btb btd btl btt daa dab dad dal dat dba dbb dbd dbl dbt dda ddb ddd ddl ddt dl- dla dlb dld dll dlt dta dtb dtd dtl dtt la- laa lab lad lal lat lba lbb lbd lbl lbt lda ldb ldd ldl ldt lla llb lld lll llt lta ltb ltd ltl ltt taa tab tad tal tat tba tbb tbd tbl tbt tda tdb tdd tdl tdt tla tld tll tlt tta ttb ttd ttl ttt