a-a a-b a-c aaa aab aac aak aar aas aau ab- aba abb abc abk abr abs abu ac- aca acb acc ack acr acs acu aka akb akc akk akr aks aku ar- ara arb arc ark arr ars aru as- asa asb asc ask asr ass asu au- aua aub auc auk aur aus b-u baa bab bac bak bar bas bau bba bbb bbc bbk bbr bbs bbu bca bcb bcc bck bcr bcs bcu bka bkb bkc bkk bkr bks bra brb brk brr brs bru bsa bsb bsc bsk bsr bss bsu bua bub buc buk bur bus buu c-- caa cab cac cak car cas cau cba cbb cbc cbk cbr cbs cbu cca ccb ccc cck ccr ccs ccu cka ckb ckc cks cra crb crc crk crr crs cru csa csb csc csk csr css csu cua cub cuc cuk cur cus cuu ka- kaa kab kac kak kar kas kau kba kbb kbc kbk kbr kbs kbu kca kcb kcc kck kcr kcs kcu kkb kkc kkk kkr kks kku kra krc krk krr krs kru ksa ksb ksc ksk ksr kss ksu kub kuc kuk kur kus kuu ra- raa rab rac rak rar ras rau rba rbb rbc rbk rbr rbs rbu rca rcb rcc rcr rcs rcu rkb rkc rkk rks rku rra rrb rrc rrk rrr rrs rru rsa rsb rsc rsk rsr rss rsu rua rub ruc ruk rur rus ruu saa sab sac sak sar sas sau sba sbb sbc sbk sbr sbs sbu sca scb scc sck scr scs scu sk- ska skb skc skk skr sks sku sr- sra srb src srk srr srs ss- ssa ssb ssc ssk ssr sss ssu sua sub suc suk sur sus suu ua- uaa uab uac uak uar uas uau uba ubb ubc ubk ubr ubs ubu uca ucb ucc uck ucr ucs ucu uka ukb ukc ukk ukr uku ur- ura urb urc urk urr urs uru usa usb usc usk usr uss usu uua uuc uur uus uuu

a-ak aaaa aaab aaac aaar aaas aaba aabb aabc aaca aacb aacc aack aacr aacs aacu aaka aaku aara aarc aars aaru aasa aasc aass aasu aaus abaa abab abac abak abar abas abau abb- abba abbb abbr abbs abca abcb abcc abcr abcs abra abrc abrs abs- absa abss absu abua abuk abus acaa acab acac acar acas acba acca accc accs accu acks acr- acra acrc acrr acrs acsa acsc acss acu- acur acus akaa akar akas akca akka akku akr- akra aksa aksu akua arab arac arak arar aras arau arba arbs arc- arca arcs arka arks arr- arra arrc arrk arrr arrs arru ars- arsa arsc arsk arsu arua arub asaa asab asac asak asar asas asau asba asbu asc- asca ascb ascc ascr aska askr asks asra asrc asrs asru assa assc assk assr asss assu asub asur asus auaa auca auks aur- aura ausa ausu baaa baak baar baas baba babb babr babs babu bac- baca bacc back bacs bak- baka bakr baks baku bar- bara barb barc bark barr bars baru basa basc bask bass basu bau- bauk baur bbas bbau bbbb bbbs bbrc bcaa bcar bcas bcbc bcbs bcca bccc bccs bcra bcrs bcru bcsa bcsc bcss bcuc brab brac brak bras brau brca brcb brka brkb brrr brrs brsb brsr bruc brus bsaa bsac bsas bscs bsra bssc buar buba bubb bubs bubu buca bucc buck bucs bucu buka bukk buku bur- bura burb burk burr burs buru busa busc busk buss busu buus caaa caab caac caas caba cabs cabu cac- caca cacc cack cacr caka cara carb carc cark carr cars casa casb casc cask casr cass casu cauc cauk caus cbac cbar cbbc cbbs cbca cbcc cbcr cbcs cbcu cbka cbkr cbsa cbsc cbus ccaa ccab ccac ccar ccas ccba ccbc ccca cccb cccc cccs cccu ccra ccrc ccrs ccsa ccss ccuc ccus ckac ckbc ckck ckcs ckrc cksa cksb crab crac crar cras crau crbc crbu crca crcc crcr crkc crsa crss crub cruk crus csaa csab csac csak csar csas cscb cscc cscr cscs cska csks csra csrc csrs cssa cssr csua csur csus cuau cub- cuba cubb cubs cuca cucc cuck cuk- cuka cura curb curr curs cusa cusb cusk cuss cusu kaaa kaab kaak kaar kaas kaba kabb kabc kabr kabu kacb kacc kacs kacu kaka kakc kakk kaks kaku kara karb kark karr kars karu kas- kasa kasb kasc kask kasr kass kasu kau- kaub kauc kauk kaur kaus kbaa kbab kbac kbak kbar kbas kbba kbbb kbbc kbbk kbbr kbbs kbbu kbca kbcb kbck kbcr kbcs kbcu kbkb kbkk kbkr kbra kbrb kbrc kbrk kbru kbsa kbsb kbsk kbsr kbss kbsu kbua kbub kbuc kbuk kbur kbus kbuu kcaa kcab kcac kcar kcas kcau kcba kcbc kcbk kcbr kcbs kcbu kcca kccb kccc kcck kccr kccu kckc kckk kckr kcrc kcrr kcrs kcru kcsa kcsb kcsc kcsr kcss kcsu kcua kcub kcuk kkaa kkac kkar kkba kkbb kkbr kkbs kkcb kkck kkcr kkcs kkkk kkrb kkrc kkrk kkrr kkrs kksa kksr kkss kksu kkua kkus kkuu krab krac krak krar kras krba krbb krbk krbr krca krcb krcc krcs krcu krka krkc krkk krkr krks krku krrb krrc krrk krrr krrs krsa krsc krsk krsr krss krsu krua kruc kruk krur ksab ksac ksak ksar ksas ksau ksba ksbc ksbr ksbs ksca kscb ksck kscr kscs kscu kska kskb kskk kskr ksks ksku ksra ksrb ksrr ksrs kssa kssr ksss kssu ksua ksub ksuu kuac kuar kuau kuba kubb kubc kubr kubs kubu kuca kucb kucc kucr kuka kukk kuks kuku kura kurb kurk kurr kurs kuru kusa kusb kusc kusu kuub kuuk kuur kuuu raab raak raas raba rabb rabk rabs rabu rac- raca racc rack racs racu raka rakk raku rara rarb rark rars rasa rasc rask rass rasu raua raub rauc rauk raus rbbb rbbr rbbs rbss rcac rcas rcbc rccb rccc rccs rcsa rcsc