a-a a-b a-c aaa aab aac aah aao aar aas aax ab- aba abb abc abh abo abr abs abx ac- aca acb acc ach aco acr acs acx aha ahb ahc ahh aho ahr ahs ahx aoa aob aoc aoh aoo aor aos aox ar- ara arb arc arh aro arr ars arx as- asa asb asc ash aso asr ass asx ax- axa axh axo axr axs axx baa bab bac bah bao bar bas bax bba bbb bbc bbh bbo bbr bbs bbx bca bcb bcc bch bco bcr bcs bcx bha bhb bhc bhh bho bhr bhs bhx boa bob boc boh boo bor bos box bra brb brh bro brr brs brx bsa bsb bsc bsh bso bsr bss bsx bxb bxo bxx c-- caa cab cac cah cao car cas cax cba cbb cbc cbh cbo cbr cbs cbx cca ccb ccc cch cco ccr ccs ccx ch- cha chb chc chh cho chr chs chx co- coa cob coc coh coo cor cos cox cra crb crc crh cro crr crs crx csa csb csc csh cso csr css csx cxc cxh cxo cxr cxs cxx haa hab hac hah hao har has hax hba hbb hbc hbh hbo hbr hbs hbx hca hcb hcc hch hco hcr hcs hha hhb hhc hhh hho hhr hhs hoa hob hoc hoh hoo hor hos hox hr- hra hrb hrc hrh hro hrr hrs hsa hsb hsc hsh hsr hss hsx hxc oaa oab oac oah oao oar oas oax ob- oba obb obc obh obo obr obs obx oc- oca ocb occ och oco ocr ocs ocx oha ohc ohh oho ohr ohs oo- ooa oob ooc ooh ooo oor oos oox or- ora orb orc orh oro orr ors orx os- osa osb osc osh oso osr oss osx ox- oxa oxb oxc oxo oxx ra- raa rab rac rah rao rar ras rax rba rbb rbc rbh rbo rbr rbs rbx rca rcb rcc rch rco rcr rcs rcx rh- rha rhb rhc rhh rho rhr rhs roa rob roc roh roo ror ros rox rra rrb rrc rrh rrr rrs rsa rsb rsc rsh rso rsr rss rsx rxr rxs saa sab sac sah sao sar sas sax sba sbb sbc sbh sbo sbr sbs sbx sca scb scc sch sco scr scs scx sh- sha shb shc shh sho shr shs soa sob soc soh soo sor sos sox sr- sra srb src srh sro srr srs srx ss- ssa ssb ssc ssh sso ssr sss ssx sxc sxs xaa xac xar xas xbc xbr xbx xcb xch xcr xcx xoa xoc xoo xor xos xox xrc xrx xsa xsb xsc xss xxo xxx