a-a a-b aaa aab aad aah aak aao aar ab- aba abb abd abh abk abo abr ad- ada adb add adh adk ado adr aha ahb ahd ahh ahk aho ahr aka akb akd akh akk ako akr aoa aob aod aoh aok aoo aor ar- ara arb ard arh ark aro arr baa bab bad bah bak bao bar bba bbb bbd bbh bbk bbo bbr bda bdb bdd bdh bdk bdo bdr bha bhb bhd bhh bhk bho bhr bka bkb bkk bko bkr boa bob bod boh bok boo bor bra brb brd brh brk bro brr daa dab dad dah dak dao dar dba dbb dbd dbh dbk dbo dbr dda ddb ddd ddh ddk ddo ddr dh- dha dhb dhd dhh dhk dho dhr dka dkb dkk dko dkr doa dob dod doh dok doo dor dra drb drd drk dro drr haa hab had hah hak hao har hba hbb hbd hbh hbk hbo hbr hda hdb hdd hdh hdk hdo hdr hha hhb hhd hhh hhk hho hhr hka hkb hkd hkh hkk hko hkr hoa hob hod hoh hok hoo hor hr- hra hrb hrd hrh hrk hro hrr ka- kaa kab kad kah kak kao kar kba kbb kbd kbh kbk kbo kbr kda kdb kdh kdk kdo kdr kha khh khk kho khr kkb kkh kkk kkr koa kob kod koh kok koo kor kra krd krk kro krr oaa oab oad oah oak oao oar ob- oba obb obd obh obk obo obr oda odb odd odh odo odr oha ohd ohh oho ohr oka okb okd okk oko okr oo- ooa oob ood ooh ook ooo oor or- ora orb ord orh ork oro orr ra- raa rab rad rah rak rao rar rba rbb rbd rbh rbk rbo rbr rda rdb rdd rdh rdo rdr rh- rha rhb rhd rhh rho rhr rkb rkk rko roa rob rod roh rok roo ror rra rrb rrd rrh rrk rrr