a-a a-b a-c aaa aab aac aad aah aao ab- aba abb abc abd abh abo ac- aca acb acc acd ach aco ad- ada adb adc add adh ado aha ahb ahc ahd ahh aho aoa aob aoc aod aoh aoo baa bab bac bad bah bao bba bbb bbc bbd bbh bbo bca bcb bcc bcd bch bco bda bdb bdc bdd bdh bdo bha bhb bhc bhd bhh bho boa bob boc bod boh boo c-- caa cab cac cad cah cao cba cbb cbc cbd cbh cbo cca ccb ccc ccd cch cco cda cdb cdc cdd cdh cdo ch- cha chb chc chd chh cho co- coa cob coc cod coh coo daa dab dac dad dah dao dba dbb dbc dbd dbh dbo dca dcb dcc dcd dco dda ddb ddc ddd ddh ddo dh- dha dhb dhc dhd dhh dho doa dob doc dod doh doo haa hab hac had hah hao hba hbb hbc hbd hbh hbo hca hcb hcc hcd hch hco hda hdb hdc hdd hdh hdo hha hhb hhc hhd hhh hho hoa hob hoc hod hoh hoo oaa oab oac oad oah oao ob- oba obb obc obd obh obo oc- oca ocb occ ocd och oco oda odb odc odd odh odo oha ohc ohd ohh oho oo- ooa oob ooc ood ooh ooo