bbb bbd bbk bbo bbr bbs bdb bdd bdk bdo bdr bds bkb bkk bko bkr bks bob bod bok boo bor bos brb brd brk bro brr brs bsb bsd bsk bso bsr bss dbb dbd dbk dbo dbr dbs ddb ddd ddk ddo ddr dds dkb dkk dko dkr dks dob dod dok doo dor dos drb drd drk dro drr drs dsb dsd dsk dso dsr dss kbb kbd kbk kbo kbr kbs kdb kdk kdo kdr kds kkb kkk kkr kks kob kod kok koo kor kos krd krk kro krr krs ksb ksd ksk kso ksr kss ob- obb obd obk obo obr obs odb odd odo odr ods okb okd okk oko okr oks oo- oob ood ook ooo oor oos or- orb ord ork oro orr ors os- osb osd osk oso osr oss rbb rbd rbk rbo rbr rbs rdb rdd rdo rdr rds rkb rkk rko rks rob rod rok roo ror ros rrb rrd rrk rrr rrs rsb rsd rsk rso rsr rss sbb sbd sbk sbo sbr sbs sdb sdd sdk sdo sdr sds sk- skb skd skk sko skr sks sob sod sok soo sor sos sr- srb srd srk sro srr srs ss- ssb ssd ssk sso ssr sss