bbb bbc bbd bbe bbo bcb bcc bcd bce bco bdb bdc bdd bde bdo be- beb bec bed bee beo bob boc bod boe boo c-- cbb cbc cbd cbe cbo ccb ccc ccd cce cco cdb cdc cdd cde cdo ce- ceb cec ced cee ceo co- cob coc cod coe coo dbb dbc dbd dbe dbo dcb dcc dcd dce dco ddb ddc ddd dde ddo de- deb dec ded dee deo dob doc dod doe doo ebb ebc ebd ebe ebo ec- ecb ecc ecd ece eco ed- edb edc edd ede edo eeb eec eed eee eeo eo- eob eoc eod eoe eoo ob- obb obc obd obe obo oc- ocb occ ocd oco odb odc odd ode odo oeb oec oed oee oeo oo- oob ooc ood ooo