bbb bbm bbn bbo bbr bmb bmm bmn bmo bmr bnb bnn bno bnr bob bom bon boo bor brb brm brn bro brr m-o m-r mbb mbm mbo mbr mmb mmm mmn mmo mmr mnb mnm mnn mno mnr mob mom mon moo mor mrb mrm mrn mro mrr nbb nbm nbn nbo nbr nmb nmm nmn nmo nmr nnb nnm nnn nno no- nob nom non noo nor nrb nrm nrn nro nrr ob- obb obm obn obo obr om- omb omm omn omo omr on- onb onn ono onr oo- oob oom oon ooo oor or- orb orm orn oro orr rbb rbm rbn rbo rbr rmb rmm rmn rmo rmr rnb rnm rnn rno rnr rob rom ron roo ror rrb rrm rrn rrr