a-a a-b a-c aaa aab aac aad aae aah aao ab- aba abb abc abd abe abh abo ac- aca acb acc acd ace ach aco ad- ada adb adc add ade adh ado aea aeb aec aed aee aeh aeo aha ahb ahc ahd ahe ahh aho aoa aob aoc aod aoe aoh aoo baa bab bac bad bae bah bao bba bbb bbc bbd bbe bbh bbo bca bcb bcc bcd bce bch bco bda bdb bdc bdd bde bdh bdo be- bea beb bec bed bee beh beo bha bhb bhc bhd bhe bhh bho boa bob boc bod boe boh boo c-- caa cab cac cad cae cah cao cba cbb cbc cbd cbe cbh cbo cca ccb ccc ccd cce cch cco cda cdb cdc cdd cde cdh cdo ce- cea ceb cec ced cee ceh ceo ch- cha chb chc chd che chh cho co- coa cob coc cod coe coh coo daa dab dac dad dae dah dao dba dbb dbc dbd dbe dbh dbo dca dcb dcc dcd dce dco dda ddb ddc ddd dde ddh ddo de- dea deb dec ded dee deh deo dh- dha dhb dhc dhd dhe dhh dho doa dob doc dod doe doh doo eaa eab eac ead eae eah eao eba ebb ebc ebd ebe ebh ebo ec- eca ecb ecc ecd ece ech eco ed- eda edb edc edd ede edh edo eea eeb eec eed eee eeo eha ehb ehc ehd ehe ehh eho eo- eoa eob eoc eod eoe eoh eoo haa hab hac had hae hah hao hba hbb hbc hbd hbe hbh hbo hca hcb hcc hcd hce hch hco hda hdb hdc hdd hde hdh hdo he- hea heb hec hed hee heh heo hha hhb hhc hhd hhe hhh hho hoa hob hoc hod hoe hoh hoo oaa oab oac oad oae oah oao ob- oba obb obc obd obe obh obo oc- oca ocb occ ocd och oco oda odb odc odd ode odh odo oea oeb oec oed oee oeh oeo oha ohc ohd ohe ohh oho oo- ooa oob ooc ood ooh ooo