b-p bbb bbk bbo bbp bbs bbt bkb bkk bko bkp bks bkt bob bok boo bop bos bot bpb bpo bpp bps bpt bsb bsk bso bsp bss bst btb btk bto btp bts btt k-t kbb kbk kbo kbp kbs kkb kkk kkp kks kkt kob kok koo kop kos kot kpk kpo kpp kps kpt ksb ksk kso ksp kss kst ktb ktk kto ktp kts ktt ob- obb obk obo obp obs obt okb okk oko okp oks oo- oob ook ooo oop oos oot op- opb opk opo opp ops opt os- osb osk oso osp oss ost ot- otb otk oto otp ots ott p-p pbb pbk pbo pbp pbs pbt pkb pko pkp pks pkt pob pok poo pop pos pot ppb ppk ppo ppp pps ppt ps- psb psk pso psp pss pst pt- ptb ptk pto ptp pts ptt sbb sbk sbo sbp sbs sbt sk- skb skk sko skp sks skt sob sok soo sop sos sot spb spk spo spp sps spt ss- ssb ssk sso ssp sss sst stb stk sto stp sts stt tbb tbk tbo tbp tbs tbt tkb tkk tko tkp tks tkt to- tob tok too top tos tot tpb tpk tpo tpp tps tpt tsb tsk tso tsp tss tst ttb ttk tto ttp tts ttt