a-a a-c a-t aaa aac aaf aan aas aat ac- aca acc acf acn acs act af- afa afc aff afn afs aft an- ana anc anf ann ans ant as- asa asc asf asn ass ast at- ata atc atf atn ats att c-- caa cac caf can cas cat cca ccc ccf ccn ccs cct cfa cfc cff cfn cfs cft cn- cna cnc cnf cnn cns cnt csa csc csf csn css cst cta ctc ctf ctn cts ctt faa fac faf fan fas fat fca fcc fcf fcn fcs fct ffa ffc fff ffn ffs fft fna fnc fnf fnn fns fnt fsa fsc fsf fsn fss fst fta ftc ftf ftn fts ftt naa nac naf nan nas nat nca ncc ncf ncn ncs nct nfa nfc nff nfn nfs nft nna nnc nnf nnn nns nnt nsa nsc nsf nsn nss nst nta ntc ntf ntn nts ntt saa sac saf san sas sat sca scc scf scn scs sct sfa sfc sff sfn sfs sft sna snc snf snn sns snt ss- ssa ssc ssf ssn sss sst sta stc stf stn sts stt taa tac taf tan tas tat tca tcc tcf tcn tcs tct tfa tfc tff tfn tfs tft tna tnc tnf tnn tns tnt tsa tsc tsf tsn tss tst tta ttc ttf ttn tts ttt