a-a a-b a-c aaa aab aac aak aan aas aav ab- aba abb abc abk abn abs abv ac- aca acb acc ack acn acs acv aka akb akc akk akn aks akv an- ana anb anc ank ann ans anv as- asa asb asc ask asn ass asv av- ava avb avc avk avn avs baa bab bac bak ban bas bav bba bbb bbc bbk bbn bbs bca bcb bcc bck bcn bcs bcv bka bkb bkc bkk bkn bks bkv bna bnb bnc bnk bnn bns bnv bsa bsb bsc bsk bsn bss bsv bva bvb bvc bvk bvn bvs bvv c-- caa cab cac cak can cas cav cba cbb cbc cbk cbn cbs cbv cca ccb ccc cck ccn ccs ccv cka ckb ckc cks cn- cna cnb cnc cnn cns cnv csa csb csc csk csn css csv cva cvb cvc cvk cvn cvs cvv ka- kaa kab kac kak kan kas kav kba kbb kbc kbk kbn kbs kca kcb kcc kck kcn kcs kkb kkc kkk kkn kks kkv kn- kna knc knk knn ksa ksb ksc ksk ksn kss ksv kva kvb kvk kvn kvs kvv naa nab nac nak nan nas nav nba nbb nbc nbk nbn nbs nbv nca ncb ncc nck ncn ncs ncv nka nkc nkk nkn nks nna nnb nnc nnk nnn nns nnv nsa nsb nsc nsk nsn nss nsv nva nvb nvc nvk nvn nvv saa sab sac sak san sas sav sba sbb sbc sbk sbn sbs sbv sca scb scc sck scn scs scv sk- ska skb skc skk sks sna snb snc snk snn sns snv ss- ssa ssb ssc ssk ssn sss ssv sva svb svc svk svn svs svv v-a vaa vab vac vak van vas vav vba vbc vbk vbs vbv vca vcc vcn vcs vka vkb vn- vna vns vnv vsa vsb vsc vsk vsn vss vsv vva vvb vvc vvs vvv