b-p bbb bbk bbo bbp bbs bkb bkk bko bkp bks bob bok boo bop bos bpb bpo bpp bps bsb bsk bso bsp bss kbb kbk kbo kbp kbs kkb kkk kkp kks kob kok koo kop kos kpk kpo kpp kps ksb ksk kso ksp kss ob- obb obk obo obp obs okb okk oko okp oks oo- oob ook ooo oop oos op- opb opk opo opp ops os- osb osk oso osp oss p-p pbb pbk pbo pbp pbs pkb pko pkp pks pob pok poo pop pos ppb ppk ppo ppp pps ps- psb psk pso psp pss sbb sbk sbo sbp sbs sk- skb skk sko skp sks sob sok soo sop sos spb spk spo spp sps ss- ssb ssk sso ssp sss