a-a a-b a-c aaa aab aac aak aan aas aau ab- aba abb abc abk abn abs abu ac- aca acb acc ack acn acs acu aka akb akc akk akn aks aku an- ana anb anc ank ann ans anu as- asa asb asc ask asn ass asu au- aua aub auc auk aun aus b-u baa bab bac bak ban bas bau bba bbb bbc bbk bbn bbs bbu bca bcb bcc bck bcn bcs bcu bka bkb bkc bkk bkn bks bna bnb bnc bnk bnn bns bnu bsa bsb bsc bsk bsn bss bsu bua bub buc buk bun bus buu c-- caa cab cac cak can cas cau cba cbb cbc cbk cbn cbs cbu cca ccb ccc cck ccn ccs ccu cka ckb ckc cks cn- cna cnb cnc cnn cns cnu csa csb csc csk csn css csu cua cub cuc cuk cun cus cuu ka- kaa kab kac kak kan kas kau kba kbb kbc kbk kbn kbs kbu kca kcb kcc kck kcn kcs kcu kkb kkc kkk kkn kks kku kn- kna knc knk knn knu ksa ksb ksc ksk ksn kss ksu kub kuc kuk kun kus kuu naa nab nac nak nan nas nau nba nbb nbc nbk nbn nbs nbu nca ncb ncc nck ncn ncs ncu nka nkc nkk nkn nks nku nna nnb nnc nnk nnn nns nnu nsa nsb nsc nsk nsn nss nsu nua nub nuc nuk nun nus nuu saa sab sac sak san sas sau sba sbb sbc sbk sbn sbs sbu sca scb scc sck scn scs scu sk- ska skb skc skk sks sku sna snb snc snk snn sns snu ss- ssa ssb ssc ssk ssn sss ssu sua sub suc suk sun sus suu ua- uaa uab uac uak uan uas uau uba ubb ubc ubk ubn ubs ubu uca ucb ucc uck ucn ucs ucu uka ukb ukc ukk ukn uku un- una unb unc unk unn uns unu usa usb usc usk usn uss usu uua uuc uun uus uuu