a-a a-b a-c a-t aaa aab aac aak aan aas aat ab- aba abb abc abk abn abs abt ac- aca acb acc ack acn acs act aka akb akc akk akn aks an- ana anb anc ank ann ans ant as- asa asb asc ask asn ass ast at- ata atb atc atn ats att baa bab bac bak ban bas bat bba bbb bbc bbk bbn bbs bbt bca bcb bcc bck bcn bcs bct bka bkb bkc bkk bkn bks bkt bna bnb bnc bnk bnn bns bnt bsa bsb bsc bsk bsn bss bst bta btb btc btk btn bts btt c-- caa cab cac cak can cas cat cba cbb cbc cbk cbn cbs cbt cca ccb ccc cck ccn ccs cct cka ckb ckc cks ckt cn- cna cnb cnc cnn cns cnt csa csb csc csk csn css cst cta ctb ctc ctk ctn cts ctt k-t ka- kaa kab kac kak kan kas kat kba kbb kbc kbk kbn kbs kca kcb kcc kck kcn kcs kct kkb kkc kkk kkn kks kkt kn- kna knc knk knn knt ksa ksb ksc ksk ksn kss kst kta ktb ktc ktk ktn kts ktt naa nab nac nak nan nas nat nba nbb nbc nbk nbn nbs nbt nca ncb ncc nck ncn ncs nct nka nkc nkk nkn nks nkt nna nnb nnc nnk nnn nns nnt nsa nsb nsc nsk nsn nss nst nta ntb ntc ntk ntn nts ntt saa sab sac sak san sas sat sba sbb sbc sbk sbn sbs sbt sca scb scc sck scn scs sct sk- ska skb skc skk sks skt sna snb snc snk snn sns snt ss- ssa ssb ssc ssk ssn sss sst sta stb stc stk stn sts stt taa tab tac tak tan tas tat tba tbb tbc tbk tbn tbs tbt tca tcb tcc tck tcn tcs tct tka tkb tkc tkk tks tkt tna tnb tnc tnk tnn tns tnt tsa tsb tsc tsk tsn tss tst tta ttb ttc ttk ttn tts ttt