a-a a-b a-c aaa aab aac aan aao aar aas aau ab- aba abb abc abn abo abr abs abu ac- aca acb acc acn aco acr acs acu an- ana anb anc ann ano anr ans anu aoa aob aoc aon aoo aor aos aou ar- ara arb arc arn aro arr ars aru as- asa asb asc asn aso asr ass asu au- aua aub auc aun auo aur aus b-u baa bab bac ban bao bar bas bau bba bbb bbc bbn bbo bbr bbs bbu bca bcb bcc bcn bco bcr bcs bcu bna bnb bnc bnn bno bnr bns bnu boa bob boc bon boo bor bos bou bra brb brn bro brr brs bru bsa bsb bsc bsn bso bsr bss bsu bua bub buc bun buo bur bus buu c-- caa cab cac can cao car cas cau cba cbb cbc cbn cbo cbr cbs cbu cca ccb ccc ccn cco ccr ccs ccu cn- cna cnb cnc cnn cno cnr cns cnu co- coa cob coc con coo cor cos cou cra crb crc crn cro crr crs cru csa csb csc csn cso csr css csu cua cub cuc cun cuo cur cus cuu naa nab nac nan nao nar nas nau nba nbb nbc nbn nbo nbr nbs nbu nca ncb ncc ncn nco ncr ncs ncu nna nnb nnc nnn nno nns nnu no- noa nob noc non noo nor nos nou nra nrb nrc nrn nro nrr nrs nru nsa nsb nsc nsn nso nsr nss nsu nua nub nuc nun nuo nur nus nuu oaa oab oac oan oao oar oas oau ob- oba obb obc obn obo obr obs obu oc- oca ocb occ ocn oco ocr ocs ocu on- ona onb onc onn ono onr ons onu oo- ooa oob ooc oon ooo oor oos or- ora orb orc orn oro orr ors oru os- osa osb osc osn oso osr oss osu ou- oua ouc oun ouo our ous ra- raa rab rac ran rao rar ras rau rba rbb rbc rbn rbo rbr rbs rbu rca rcb rcc rcn rco rcr rcs rcu rna rnb rnc rnn rno rnr rns rnu roa rob roc ron roo ror ros rou rra rrb rrc rrn rrr rrs rru rsa rsb rsc rsn rso rsr rss rsu rua rub ruc run ruo rur rus ruu saa sab sac san sao sar sas sau sba sbb sbc sbn sbo sbr sbs sbu sca scb scc scn sco scr scs scu sna snb snc snn sno snr sns snu soa sob soc son soo sor sos sou sr- sra srb src srn sro srr srs ss- ssa ssb ssc ssn sso ssr sss ssu sua sub suc sun suo sur sus suu ua- uaa uab uac uan uao uar uas uau uba ubb ubc ubn ubo ubr ubs ubu uca ucb ucc ucn uco ucr ucs ucu un- una unb unc unn uno unr uns unu uoa uob uoc uon uoo uor uos ur- ura urb urc urn uro urr urs uru usa usb usc usn uso usr uss usu uua uuc uun uur uus uuu