bbb bbc bbd bbe bbo bbt bcb bcc bcd bce bco bct bdb bdc bdd bde bdo bdt be- beb bec bed bee beo bet bob boc bod boe boo bot btb btc btd bte bto btt c-- cbb cbc cbd cbe cbo cbt ccb ccc ccd cce cco cct cdb cdc cdd cde cdo cdt ce- ceb cec ced cee ceo cet co- cob coc cod coe coo cot ctb ctc ctd cte cto ctt dbb dbc dbd dbe dbo dbt dcb dcc dcd dce dco dct ddb ddc ddd dde ddo ddt de- deb dec ded dee deo det dob doc dod doe doo dot dtb dtc dtd dte dto dtt ebb ebc ebd ebe ebo ebt ec- ecb ecc ecd ece eco ect ed- edb edc edd ede edo edt eeb eec eed eee eeo eet eo- eob eoc eod eoe eoo eot etb etc etd ete eto ett ob- obb obc obd obe obo obt oc- ocb occ ocd oco oct odb odc odd ode odo odt oeb oec oed oee oeo oet oo- oob ooc ood ooo oot ot- otb otc otd ote oto ott tbb tbc tbd tbe tbo tbt tcb tcc tcd tce tco tct tdb tdc tdd tde tdo tdt te- teb tec ted tee teo tet to- tob toc tod toe too tot ttb ttc ttd tte tto ttt