b-p bbb bbn bbo bbp bbr bnb bnn bno bnp bnr bob bon boo bop bor bpb bpn bpo bpp bpr brb brn bro brp brr nbb nbn nbo nbp nbr nnb nnn nno nnp no- nob non noo nop nor npb npn npo npp npr nrb nrn nro nrp nrr ob- obb obn obo obp obr on- onb onn ono onp onr oo- oob oon ooo oop oor op- opb opn opo opp opr or- orb orn oro orp orr p-p pbb pbn pbo pbp pbr pn- pnb pnn pno pnp pnr pob pon poo pop por ppb ppn ppo ppp ppr prb prn pro prp prr rbb rbn rbo rbp rbr rnb rnn rno rnp rnr rob ron roo rop ror rpb rpn rpo rpp rpr rrb rrn rrp rrr