a-a a-c a-t aaa aac aad aaf aas aat ac- aca acc acd acf acs act ad- ada adc add adf ads adt af- afa afc afd aff afs aft as- asa asc asd asf ass ast at- ata atc atd atf ats att c-- caa cac cad caf cas cat cca ccc ccd ccf ccs cct cda cdc cdd cdf cds cdt cfa cfc cfd cff cfs cft csa csc csd csf css cst cta ctc ctd ctf cts ctt daa dac dad daf das dat dca dcc dcd dcf dcs dct dda ddc ddd ddf dds ddt dfa dfc dfd dff dfs dft dsa dsc dsd dsf dss dst dta dtc dtd dtf dts dtt faa fac fad faf fas fat fca fcc fcd fcf fcs fct fda fdc fdd fdf fds fdt ffa ffc ffd fff ffs fft fsa fsc fsd fsf fss fst fta ftc ftd ftf fts ftt saa sac sad saf sas sat sca scc scd scf scs sct sda sdc sdd sdf sds sdt sfa sfc sfd sff sfs sft ss- ssa ssc ssd ssf sss sst sta stc std stf sts stt taa tac tad taf tas tat tca tcc tcd tcf tcs tct tda tdc tdd tdf tds tdt tfa tfc tfd tff tfs tft tsa tsc tsd tsf tss tst tta ttc ttd ttf tts ttt