a-a a-b a-c aaa aab aac aah aao aar aas ab- aba abb abc abh abo abr abs ac- aca acb acc ach aco acr acs aha ahb ahc ahh aho ahr ahs aoa aob aoc aoh aoo aor aos ar- ara arb arc arh aro arr ars as- asa asb asc ash aso asr ass baa bab bac bah bao bar bas bba bbb bbc bbh bbo bbr bbs bca bcb bcc bch bco bcr bcs bha bhb bhc bhh bho bhr bhs boa bob boc boh boo bor bos bra brb brh bro brr brs bsa bsb bsc bsh bso bsr bss c-- caa cab cac cah cao car cas cba cbb cbc cbh cbo cbr cbs cca ccb ccc cch cco ccr ccs ch- cha chb chc chh cho chr chs co- coa cob coc coh coo cor cos cra crb crc crh cro crr crs csa csb csc csh cso csr css haa hab hac hah hao har has hba hbb hbc hbh hbo hbr hbs hca hcb hcc hch hco hcr hcs hha hhb hhc hhh hho hhr hhs hoa hob hoc hoh hoo hor hos hr- hra hrb hrc hrh hro hrr hrs hsa hsb hsc hsh hsr hss oaa oab oac oah oao oar oas ob- oba obb obc obh obo obr obs oc- oca ocb occ och oco ocr ocs oha ohc ohh oho ohr ohs oo- ooa oob ooc ooh ooo oor oos or- ora orb orc orh oro orr ors os- osa osb osc osh oso osr oss ra- raa rab rac rah rao rar ras rba rbb rbc rbh rbo rbr rbs rca rcb rcc rch rco rcr rcs rh- rha rhb rhc rhh rho rhr rhs roa rob roc roh roo ror ros rra rrb rrc rrh rrr rrs rsa rsb rsc rsh rso rsr rss saa sab sac sah sao sar sas sba sbb sbc sbh sbo sbr sbs sca scb scc sch sco scr scs sh- sha shb shc shh sho shr shs soa sob soc soh soo sor sos sr- sra srb src srh sro srr srs ss- ssa ssb ssc ssh sso ssr sss