-ol bbb bbl bbm bbo bbr blb bll blm blo blr bmb bml bmm bmo bmr bob bol bom boo bor brb brl brm bro brr lbb lbl lbm lbo lbr llb lll llm llo llr lmb lml lmm lmo lmr lob lol lom loo lor lrb lrm lro lrr m-o m-r mbb mbl mbm mbo mbr mlb mll mlm mlo mlr mmb mml mmm mmo mmr mob mol mom moo mor mrb mrl mrm mro mrr ob- obb obl obm obo obr olb oll olm olo om- omb oml omm omo omr oo- oob ool oom ooo oor or- orb orl orm oro orr rbb rbl rbm rbo rbr rll rlm rlo rlr rmb rml rmm rmo rmr rob rol rom roo ror rrb rrl rrm rrr