a-a a-b a-c aaa aab aac aad aae aah aak aao ab- aba abb abc abd abe abh abk abo ac- aca acb acc acd ace ach ack aco ad- ada adb adc add ade adh adk ado aea aeb aec aed aee aeh aek aeo aha ahb ahc ahd ahe ahh ahk aho aka akb akc akd ake akh akk ako aoa aob aoc aod aoe aoh aok aoo baa bab bac bad bae bah bak bao bba bbb bbc bbd bbe bbh bbk bbo bca bcb bcc bcd bce bch bck bco bda bdb bdc bdd bde bdh bdk bdo be- bea beb bec bed bee beh bek beo bha bhb bhc bhd bhe bhh bhk bho bka bkb bkc bke bkk bko boa bob boc bod boe boh bok boo c-- caa cab cac cad cae cah cak cao cba cbb cbc cbd cbe cbh cbk cbo cca ccb ccc ccd cce cch cck cco cda cdb cdc cdd cde cdh cdk cdo ce- cea ceb cec ced cee ceh cek ceo ch- cha chb chc chd che chh chk cho cka ckb ckc ckd ckh cko co- coa cob coc cod coe coh cok coo daa dab dac dad dae dah dak dao dba dbb dbc dbd dbe dbh dbk dbo dca dcb dcc dcd dce dck dco dda ddb ddc ddd dde ddh ddk ddo de- dea deb dec ded dee deh dek deo dh- dha dhb dhc dhd dhe dhh dhk dho dka dkb dkc dke dkk dko doa dob doc dod doe doh dok doo eaa eab eac ead eae eah eak eao eba ebb ebc ebd ebe ebh ebk ebo ec- eca ecb ecc ecd ece ech eck eco ed- eda edb edc edd ede edh edk edo eea eeb eec eed eee eek eeo eha ehb ehc ehd ehe ehh eho eka ekb ekc ekd eke ekh eko eo- eoa eob eoc eod eoe eoh eok eoo haa hab hac had hae hah hak hao hba hbb hbc hbd hbe hbh hbk hbo hca hcb hcc hcd hce hch hck hco hda hdb hdc hdd hde hdh hdk hdo he- hea heb hec hed hee heh hek heo hha hhb hhc hhd hhe hhh hhk hho hka hkb hkd hkh hkk hko hoa hob hoc hod hoe hoh hok hoo ka- kaa kab kac kad kae kah kak kao kba kbb kbc kbd kbe kbh kbk kbo kca kcb kcc kcd kce kch kck kda kdb kdc kde kdh kdk kdo ke- kea keb kec ked kee keh kek keo kha khe khh khk kho kkb kkc kke kkh kkk koa kob koc kod koe koh kok koo oaa oab oac oad oae oah oak oao ob- oba obb obc obd obe obh obk obo oc- oca ocb occ ocd och ock oco oda odb odc odd ode odh odo oea oeb oec oed oee oeh oeo oha ohc ohd ohe ohh oho oka okb okc okd oke okk oko oo- ooa oob ooc ood ooh ook ooo