bbb bbc bbd bbe bbk bbo bcb bcc bcd bce bck bco bdb bdc bdd bde bdk bdo be- beb bec bed bee bek beo bkb bkc bke bkk bko bob boc bod boe bok boo c-- cbb cbc cbd cbe cbk cbo ccb ccc ccd cce cck cco cdb cdc cdd cde cdk cdo ce- ceb cec ced cee cek ceo ckb ckc ckd cko co- cob coc cod coe cok coo dbb dbc dbd dbe dbk dbo dcb dcc dcd dce dck dco ddb ddc ddd dde ddk ddo de- deb dec ded dee dek deo dkb dkc dke dkk dko dob doc dod doe dok doo ebb ebc ebd ebe ebk ebo ec- ecb ecc ecd ece eck eco ed- edb edc edd ede edk edo eeb eec eed eee eek eeo ekb ekc ekd eke eko eo- eob eoc eod eoe eok eoo kbb kbc kbd kbe kbk kbo kcb kcc kcd kce kck kdb kdc kde kdk kdo ke- keb kec ked kee kek keo kkb kkc kke kkk kob koc kod koe kok koo ob- obb obc obd obe obk obo oc- ocb occ ocd ock oco odb odc odd ode odo oeb oec oed oee oeo okb okc okd oke okk oko oo- oob ooc ood ook ooo