a-a a-b a-c aaa aab aac aak aan aar aas aau ab- aba abb abc abk abn abr abs abu ac- aca acb acc ack acn acr acs acu aka akb akc akk akn akr aks aku an- ana anb anc ank ann anr ans anu ar- ara arb arc ark arn arr ars aru as- asa asb asc ask asn asr ass asu au- aua aub auc auk aun aur aus b-u baa bab bac bak ban bar bas bau bba bbb bbc bbk bbn bbr bbs bbu bca bcb bcc bck bcn bcr bcs bcu bka bkb bkc bkk bkn bkr bks bna bnb bnc bnk bnn bnr bns bnu bra brb brk brn brr brs bru bsa bsb bsc bsk bsn bsr bss bsu bua bub buc buk bun bur bus buu c-- caa cab cac cak can car cas cau cba cbb cbc cbk cbn cbr cbs cbu cca ccb ccc cck ccn ccr ccs ccu cka ckb ckc cks cn- cna cnb cnc cnn cnr cns cnu cra crb crc crk crn crr crs cru csa csb csc csk csn csr css csu cua cub cuc cuk cun cur cus cuu ka- kaa kab kac kak kan kar kas kau kba kbb kbc kbk kbn kbr kbs kbu kca kcb kcc kck kcn kcr kcs kcu kkb kkc kkk kkn kkr kks kku kn- kna knc knk knn knr knu kra krc krk krn krr krs kru ksa ksb ksc ksk ksn ksr kss ksu kub kuc kuk kun kur kus kuu naa nab nac nak nan nar nas nau nba nbb nbc nbk nbn nbr nbs nbu nca ncb ncc nck ncn ncr ncs ncu nka nkc nkk nkn nkr nks nku nna nnb nnc nnk nnn nns nnu nra nrb nrc nrk nrn nrr nrs nru nsa nsb nsc nsk nsn nsr nss nsu nua nub nuc nuk nun nur nus nuu ra- raa rab rac rak ran rar ras rau rba rbb rbc rbk rbn rbr rbs rbu rca rcb rcc rcn rcr rcs rcu rkb rkc rkk rks rku rna rnb rnc rnn rnr rns rnu rra rrb rrc rrk rrn rrr rrs rru rsa rsb rsc rsk rsn rsr rss rsu rua rub ruc ruk run rur rus ruu saa sab sac sak san sar sas sau sba sbb sbc sbk sbn sbr sbs sbu sca scb scc sck scn scr scs scu sk- ska skb skc skk skr sks sku sna snb snc snk snn snr sns snu sr- sra srb src srk srn srr srs ss- ssa ssb ssc ssk ssn ssr sss ssu sua sub suc suk sun sur sus suu ua- uaa uab uac uak uan uar uas uau uba ubb ubc ubk ubn ubr ubs ubu uca ucb ucc uck ucn ucr ucs ucu uka ukb ukc ukk ukn ukr uku un- una unb unc unk unn unr uns unu ur- ura urb urc urk urn urr urs uru usa usb usc usk usn usr uss usu uua uuc uun uur uus uuu