a-a a-b a-c aaa aab aac aao aar aas aau aay ab- aba abb abc abo abr abs abu aby ac- aca acb acc aco acr acs acu acy aoa aob aoc aoo aor aos aou ar- ara arb arc aro arr ars aru ary as- asa asb asc aso asr ass asu asy au- aua aub auc auo aur aus ay- aya ayc ayo ayr ays ayu b-u baa bab bac bao bar bas bau bay bba bbb bbc bbo bbr bbs bbu bby bca bcb bcc bco bcr bcs bcu bcy boa bob boc boo bor bos bou boy bra brb bro brr brs bru bry bsa bsb bsc bso bsr bss bsu bsy bua bub buc buo bur bus buu buy by- bya byc byo byr bys byu c-- caa cab cac cao car cas cau cay cba cbb cbc cbo cbr cbs cbu cby cca ccb ccc cco ccr ccs ccu co- coa cob coc coo cor cos cou coy cra crb crc cro crr crs cru cry csa csb csc cso csr css csu csy cua cub cuc cuo cur cus cuu cuy cya cyb cyc cyo cyr cys oaa oab oac oao oar oas oau ob- oba obb obc obo obr obs obu oby oc- oca ocb occ oco ocr ocs ocu oo- ooa oob ooc ooo oor oos or- ora orb orc oro orr ors oru ory os- osa osb osc oso osr oss osu ou- oua ouc ouo our ous oya oyo oys ra- raa rab rac rao rar ras rau ray rba rbb rbc rbo rbr rbs rbu rca rcb rcc rco rcr rcs rcu roa rob roc roo ror ros rou roy rra rrb rrc rrr rrs rru rsa rsb rsc rso rsr rss rsu rua rub ruc ruo rur rus ruu ruy ry- rya ryc ryo ryr rys ryu ryy saa sab sac sao sar sas sau say sba sbb sbc sbo sbr sbs sbu sby sca scb scc sco scr scs scu soa sob soc soo sor sos sou soy sr- sra srb src sro srr srs sry ss- ssa ssb ssc sso ssr sss ssu sua sub suc suo sur sus suu suy sy- sya syb syc syr sys syu ua- uaa uab uac uao uar uas uau uay uba ubb ubc ubo ubr ubs ubu uby uca ucb ucc uco ucr ucs ucu uoa uob uoc uoo uor uos ur- ura urb urc uro urr urs uru ury usa usb usc uso usr uss usu uua uuc uur uus uuu uyc uyo uys uyu yaa yab yac yao yar yas yau yay ybc ybr ybs yby yca ycc yco ycs ycu ycy yob yoc yoo yor yos you yoy yra yrc yro yrs yru ysa ysb ysc yso ysr yss ysu ysy yua yuo yur yus yuu yuy yyb yyc yys yyu yyy