a-a a-b a-c aaa aab aac aad aah aak aao aar ab- aba abb abc abd abh abk abo abr ac- aca acb acc acd ach ack aco acr ad- ada adb adc add adh adk ado adr aha ahb ahc ahd ahh ahk aho ahr aka akb akc akd akh akk ako akr aoa aob aoc aod aoh aok aoo aor ar- ara arb arc ard arh ark aro arr baa bab bac bad bah bak bao bar bba bbb bbc bbd bbh bbk bbo bbr bca bcb bcc bcd bch bck bco bcr bda bdb bdc bdd bdh bdk bdo bdr bha bhb bhc bhd bhh bhk bho bhr bka bkb bkc bkk bko bkr boa bob boc bod boh bok boo bor bra brb brd brh brk bro brr c-- caa cab cac cad cah cak cao car cba cbb cbc cbd cbh cbk cbo cbr cca ccb ccc ccd cch cck cco ccr cda cdb cdc cdd cdh cdk cdo cdr ch- cha chb chc chd chh chk cho chr cka ckb ckc ckd ckh cko co- coa cob coc cod coh cok coo cor cra crb crc crd crh crk cro crr daa dab dac dad dah dak dao dar dba dbb dbc dbd dbh dbk dbo dbr dca dcb dcc dcd dck dco dcr dda ddb ddc ddd ddh ddk ddo ddr dh- dha dhb dhc dhd dhh dhk dho dhr dka dkb dkc dkk dko dkr doa dob doc dod doh dok doo dor dra drb drc drd drk dro drr haa hab hac had hah hak hao har hba hbb hbc hbd hbh hbk hbo hbr hca hcb hcc hcd hch hck hco hcr hda hdb hdc hdd hdh hdk hdo hdr hha hhb hhc hhd hhh hhk hho hhr hka hkb hkd hkh hkk hko hkr hoa hob hoc hod hoh hok hoo hor hr- hra hrb hrc hrd hrh hrk hro hrr ka- kaa kab kac kad kah kak kao kar kba kbb kbc kbd kbh kbk kbo kbr kca kcb kcc kcd kch kck kcr kda kdb kdc kdh kdk kdo kdr kha khh khk kho khr kkb kkc kkh kkk kkr koa kob koc kod koh kok koo kor kra krc krd krk kro krr oaa oab oac oad oah oak oao oar ob- oba obb obc obd obh obk obo obr oc- oca ocb occ ocd och ock oco ocr oda odb odc odd odh odo odr oha ohc ohd ohh oho ohr oka okb okc okd okk oko okr oo- ooa oob ooc ood ooh ook ooo oor or- ora orb orc ord orh ork oro orr ra- raa rab rac rad rah rak rao rar rba rbb rbc rbd rbh rbk rbo rbr rca rcb rcc rcd rch rco rcr rda rdb rdc rdd rdh rdo rdr rh- rha rhb rhc rhd rhh rho rhr rkb rkc rkk rko roa rob roc rod roh rok roo ror rra rrb rrc rrd rrh rrk rrr