-ol bbb bbc bbl bbm bbo bbt bcb bcc bcl bcm bco bct blb blc bll blm blo blt bmb bmc bml bmm bmo bmt bob boc bol bom boo bot btb btc btl btm bto btt c-- cbb cbc cbl cbm cbo cbt ccb ccc ccl ccm cco cct cl- clb clc cll clm clo clt cmb cmc cml cmm cmo cmt co- cob coc col com coo cot ctb ctc ctl ctm cto ctt lbb lbc lbl lbm lbo lbt lcb lcc lcl lcm lco lct llb llc lll llm llo llt lmb lmc lml lmm lmo lmt lob loc lol lom loo lot ltb ltc ltl ltm lto ltt m-o mbb mbc mbl mbm mbo mbt mc- mcb mcc mcl mcm mco mct mlb mlc mll mlm mlo mlt mmb mmc mml mmm mmo mmt mob moc mol mom moo mot mtb mtc mtl mtm mto mtt ob- obb obc obl obm obo obt oc- ocb occ ocl ocm oco oct olb olc oll olm olo olt om- omb omc oml omm omo omt oo- oob ooc ool oom ooo oot ot- otb otc otl otm oto ott tbb tbc tbl tbm tbo tbt tcb tcc tcl tcm tco tct tlc tll tlm tlo tlt tmb tmc tml tmm tmo tmt to- tob toc tol tom too tot ttb ttc ttl ttm tto ttt