a-a a-b a-c aaa aab aac aah aao aas aay ab- aba abb abc abh abo abs aby ac- aca acb acc ach aco acs acy aha ahb ahc ahh aho ahs ahy aoa aob aoc aoh aoo aos as- asa asb asc ash aso ass asy ay- aya ayc ayh ayo ays baa bab bac bah bao bas bay bba bbb bbc bbh bbo bbs bby bca bcb bcc bch bco bcs bcy bha bhb bhc bhh bho bhs boa bob boc boh boo bos boy bsa bsb bsc bsh bso bss bsy by- bya byc byh byo bys c-- caa cab cac cah cao cas cay cba cbb cbc cbh cbo cbs cby cca ccb ccc cch cco ccs ch- cha chb chc chh cho chs chy co- coa cob coc coh coo cos coy csa csb csc csh cso css csy cya cyb cyc cyo cys haa hab hac hah hao has hay hba hbb hbc hbh hbo hbs hby hca hcb hcc hch hco hcs hcy hha hhb hhc hhh hho hhs hhy hoa hob hoc hoh hoo hos hoy hsa hsb hsc hsh hss hsy hy- hya hyb hyc hyh hyo hys hyy oaa oab oac oah oao oas ob- oba obb obc obh obo obs oby oc- oca ocb occ och oco ocs oha ohc ohh oho ohs oo- ooa oob ooc ooh ooo oos os- osa osb osc osh oso oss oya oyo oys saa sab sac sah sao sas say sba sbb sbc sbh sbo sbs sby sca scb scc sch sco scs sh- sha shb shc shh sho shs shy soa sob soc soh soo sos soy ss- ssa ssb ssc ssh sso sss sy- sya syb syc syh sys yaa yab yac yah yao yas yay ybc ybs yby yca ycc ych yco ycs ycy yha yhc yhs yob yoc yoo yos yoy ysa ysb ysc yso yss ysy yyb yyc yys yyy