a-a a-b a-c a-t aaa aab aac aad aat ab- aba abb abc abd abt ac- aca acb acc acd act ad- ada adb adc add adt at- ata atb atc atd att baa bab bac bad bat bba bbb bbc bbd bbt bca bcb bcc bcd bct bda bdb bdc bdd bdt bta btb btc btd btt c-- caa cab cac cad cat cba cbb cbc cbd cbt cca ccb ccc ccd cct cda cdb cdc cdd cdt cta ctb ctc ctd ctt daa dab dac dad dat dba dbb dbc dbd dbt dca dcb dcc dcd dct dda ddb ddc ddd ddt dta dtb dtc dtd dtt taa tab tac tad tat tba tbb tbc tbd tbt tca tcb tcc tcd tct tda tdb tdc tdd tdt tta ttb ttc ttd ttt