b-p bbb bbk bbo bbp bbr bbs bbt bkb bkk bko bkp bkr bks bkt bob bok boo bop bor bos bot bpb bpo bpp bpr bps bpt brb brk bro brp brr brs brt bsb bsk bso bsp bsr bss bst btb btk bto btp btr bts btt k-t kbb kbk kbo kbp kbr kbs kkb kkk kkp kkr kks kkt kob kok koo kop kor kos kot kpk kpo kpp kpr kps kpt krk kro krp krr krs krt ksb ksk kso ksp ksr kss kst ktb ktk kto ktp ktr kts ktt ob- obb obk obo obp obr obs obt okb okk oko okp okr oks oo- oob ook ooo oop oor oos oot op- opb opk opo opp opr ops opt or- orb ork oro orp orr ors ort os- osb osk oso osp osr oss ost ot- otb otk oto otp otr ots ott p-p pbb pbk pbo pbp pbr pbs pbt pkb pko pkp pkr pks pkt pob pok poo pop por pos pot ppb ppk ppo ppp ppr pps ppt prb prk pro prp prr prs prt ps- psb psk pso psp psr pss pst pt- ptb ptk pto ptp ptr pts ptt rbb rbk rbo rbp rbr rbs rbt rkb rkk rko rkp rks rkt rob rok roo rop ror ros rot rpb rpk rpo rpp rpr rps rpt rrb rrk rrp rrr rrs rrt rsb rsk rso rsp rsr rss rst rtb rtk rto rtp rtr rts rtt sbb sbk sbo sbp sbr sbs sbt sk- skb skk sko skp skr sks skt sob sok soo sop sor sos sot spb spk spo spp spr sps spt sr- srb srk sro srp srr srs srt ss- ssb ssk sso ssp ssr sss sst stb stk sto stp str sts stt tbb tbk tbo tbp tbr tbs tbt tkb tkk tko tkp tkr tks tkt to- tob tok too top tor tos tot tpb tpk tpo tpp tpr tps tpt trb trk tro trp trr trs trt tsb tsk tso tsp tsr tss tst ttb ttk tto ttp ttr tts ttt