a-a a-b a-c aaa aab aac aad aak aar aas aau ab- aba abb abc abd abk abr abs abu ac- aca acb acc acd ack acr acs acu ad- ada adb adc add adk adr ads adu aka akb akc akd akk akr aks aku ar- ara arb arc ard ark arr ars aru as- asa asb asc asd ask asr ass asu au- aua aub auc aud auk aur aus b-u baa bab bac bad bak bar bas bau bba bbb bbc bbd bbk bbr bbs bbu bca bcb bcc bcd bck bcr bcs bcu bda bdb bdc bdd bdk bdr bds bdu bka bkb bkc bkk bkr bks bra brb brd brk brr brs bru bsa bsb bsc bsd bsk bsr bss bsu bua bub buc bud buk bur bus buu c-- caa cab cac cad cak car cas cau cba cbb cbc cbd cbk cbr cbs cbu cca ccb ccc ccd cck ccr ccs ccu cda cdb cdc cdd cdk cdr cds cdu cka ckb ckc ckd cks cra crb crc crd crk crr crs cru csa csb csc csd csk csr css csu cua cub cuc cud cuk cur cus cuu daa dab dac dad dak dar das dau dba dbb dbc dbd dbk dbr dbs dbu dca dcb dcc dcd dck dcr dcs dcu dda ddb ddc ddd ddk ddr dds ddu dka dkb dkc dkk dkr dks dku dra drb drc drd drk drr drs dru dsa dsb dsc dsd dsk dsr dss dsu dua dub duc dud duk dur dus ka- kaa kab kac kad kak kar kas kau kba kbb kbc kbd kbk kbr kbs kbu kca kcb kcc kcd kck kcr kcs kcu kda kdb kdc kdk kdr kds kdu kkb kkc kkk kkr kks kku kra krc krd krk krr krs kru ksa ksb ksc ksd ksk ksr kss ksu kub kuc kud kuk kur kus kuu ra- raa rab rac rad rak rar ras rau rba rbb rbc rbd rbk rbr rbs rbu rca rcb rcc rcd rcr rcs rcu rda rdb rdc rdd rdr rds rdu rkb rkc rkk rks rku rra rrb rrc rrd rrk rrr rrs rru rsa rsb rsc rsd rsk rsr rss rsu rua rub ruc rud ruk rur rus ruu saa sab sac sad sak sar sas sau sba sbb sbc sbd sbk sbr sbs sbu sca scb scc scd sck scr scs scu sda sdb sdc sdd sdk sdr sds sdu sk- ska skb skc skd skk skr sks sku sr- sra srb src srd srk srr srs ss- ssa ssb ssc ssd ssk ssr sss ssu sua sub suc sud suk sur sus suu ua- uaa uab uac uad uak uar uas uau uba ubb ubc ubk ubr ubs ubu uca ucb ucc ucd uck ucr ucs ucu uda udb udc udd udk udr uds udu uka ukb ukc ukk ukr uku ur- ura urb urc urd urk urr urs uru usa usb usc usd usk usr uss usu uua uuc uur uus uuu