a-a a-b aaa aab aad aah aak aao ab- aba abb abd abh abk abo ad- ada adb add adh adk ado aha ahb ahd ahh ahk aho aka akb akd akh akk ako aoa aob aod aoh aok aoo baa bab bad bah bak bao bba bbb bbd bbh bbk bbo bda bdb bdd bdh bdk bdo bha bhb bhd bhh bhk bho bka bkb bkk bko boa bob bod boh bok boo daa dab dad dah dak dao dba dbb dbd dbh dbk dbo dda ddb ddd ddh ddk ddo dh- dha dhb dhd dhh dhk dho dka dkb dkk dko doa dob dod doh dok doo haa hab had hah hak hao hba hbb hbd hbh hbk hbo hda hdb hdd hdh hdk hdo hha hhb hhd hhh hhk hho hka hkb hkd hkh hkk hko hoa hob hod hoh hok hoo ka- kaa kab kad kah kak kao kba kbb kbd kbh kbk kbo kda kdb kdh kdk kdo kha khh khk kho kkb kkh kkk koa kob kod koh kok koo oaa oab oad oah oak oao ob- oba obb obd obh obk obo oda odb odd odh odo oha ohd ohh oho oka okb okd okk oko oo- ooa oob ood ooh ook ooo