b-p bbb bbf bbk bbo bbp bbs bfb bff bfo bfp bfs bkb bkf bkk bko bkp bks bob bof bok boo bop bos bpb bpf bpo bpp bps bsb bsf bsk bso bsp bss fbb fbf fbk fbo fbp fbs fff ffk ffo ffp ffs fkb fkf fkk fkp fob fof fok foo fop fos fpb fpk fpo fpp fps fsb fsf fsk fso fsp fss kbb kbf kbk kbo kbp kbs kff kfo kfs kkb kkk kkp kks kob kof kok koo kop kos kpf kpk kpo kpp kps ksb ksf ksk kso ksp kss ob- obb obf obk obo obp obs of- ofb off ofo ofp ofs okb okk oko okp oks oo- oob oof ook ooo oop oos op- opb opf opk opo opp ops os- osb osf osk oso osp oss p-p pbb pbf pbk pbo pbp pbs pfb pff pfk pfo pfp pfs pkb pkf pko pkp pks pob pof pok poo pop pos ppb ppf ppk ppo ppp pps ps- psb psf psk pso psp pss sbb sbf sbk sbo sbp sbs sfb sff sfk sfo sfp sfs sk- skb skf skk sko skp sks sob sof sok soo sop sos spb spf spk spo spp sps ss- ssb ssf ssk sso ssp sss