b-p bbb bbn bbp bbr bbs bnb bnn bnp bnr bns bpb bpn bpp bpr bps brb brn brp brr brs bsb bsn bsp bsr bss nbb nbn nbp nbr nbs nnb nnn nnp nns npb npn npp npr nps nrb nrn nrp nrr nrs nsb nsn nsp nsr nss p-p pbb pbn pbp pbr pbs pn- pnb pnn pnp pnr pns ppb ppn ppp ppr pps prb prn prp prr prs ps- psb psn psp psr pss rbb rbn rbp rbr rbs rnb rnn rnp rnr rns rpb rpn rpp rpr rps rrb rrn rrp rrr rrs rsb rsn rsp rsr rss sbb sbn sbp sbr sbs snb snn snp snr sns spb spn spp spr sps sr- srb srn srp srr srs ss- ssb ssn ssp ssr sss