-ol bbb bbc bbd bbl bbo bbt bcb bcc bcd bcl bco bct bdb bdc bdd bdl bdo bdt blb blc bld bll blo blt bob boc bod bol boo bot btb btc btd btl bto btt c-- cbb cbc cbd cbl cbo cbt ccb ccc ccd ccl cco cct cdb cdc cdd cdl cdo cdt cl- clb clc cld cll clo clt co- cob coc cod col coo cot ctb ctc ctd ctl cto ctt dbb dbc dbd dbl dbo dbt dcb dcc dcd dcl dco dct ddb ddc ddd ddl ddo ddt dl- dlb dlc dld dll dlo dlt dob doc dod dol doo dot dtb dtc dtd dtl dto dtt lbb lbc lbd lbl lbo lbt lcb lcc lcd lcl lco lct ldb ldc ldd ldl ldo ldt llb llc lld lll llo llt lob loc lod lol loo lot ltb ltc ltd ltl lto ltt ob- obb obc obd obl obo obt oc- ocb occ ocd ocl oco oct odb odc odd odl odo odt olb olc old oll olo olt oo- oob ooc ood ool ooo oot ot- otb otc otd otl oto ott tbb tbc tbd tbl tbo tbt tcb tcc tcd tcl tco tct tdb tdc tdd tdl tdo tdt tlc tld tll tlo tlt to- tob toc tod tol too tot ttb ttc ttd ttl tto ttt