b-p bbb bbd bbo bbp bbr bbs bbt bdb bdd bdo bdp bdr bds bdt bob bod boo bop bor bos bot bpb bpd bpo bpp bpr bps bpt brb brd bro brp brr brs brt bsb bsd bso bsp bsr bss bst btb btd bto btp btr bts btt dbb dbd dbo dbp dbr dbs dbt ddb ddd ddo ddp ddr dds ddt dob dod doo dop dor dos dot dpb dpd dpo dpp dpr dps dpt drb drd dro drp drr drs drt dsb dsd dso dsp dsr dss dst dtb dtd dto dtp dtr dts dtt ob- obb obd obo obp obr obs obt odb odd odo odp odr ods odt oo- oob ood ooo oop oor oos oot op- opb opd opo opp opr ops opt or- orb ord oro orp orr ors ort os- osb osd oso osp osr oss ost ot- otb otd oto otp otr ots ott p-p pbb pbd pbo pbp pbr pbs pbt pdb pdd pdo pdp pdr pds pdt pob pod poo pop por pos pot ppb ppd ppo ppp ppr pps ppt prb prd pro prp prr prs prt ps- psb psd pso psp psr pss pst pt- ptb ptd pto ptp ptr pts ptt rbb rbd rbo rbp rbr rbs rbt rdb rdd rdo rdp rdr rds rdt rob rod roo rop ror ros rot rpb rpd rpo rpp rpr rps rpt rrb rrd rrp rrr rrs rrt rsb rsd rso rsp rsr rss rst rtb rtd rto rtp rtr rts rtt sbb sbd sbo sbp sbr sbs sbt sdb sdd sdo sdp sdr sds sdt sob sod soo sop sor sos sot spb spd spo spp spr sps spt sr- srb srd sro srp srr srs srt ss- ssb ssd sso ssp ssr sss sst stb std sto stp str sts stt tbb tbd tbo tbp tbr tbs tbt tdb tdd tdo tdp tdr tds tdt to- tob tod too top tor tos tot tpb tpd tpo tpp tpr tps tpt trb trd tro trp trr trs trt tsb tsd tso tsp tsr tss tst ttb ttd tto ttp ttr tts ttt