bbb bbc bbd bbk bbn bbo bbs bcb bcc bcd bck bcn bco bcs bdb bdc bdd bdk bdo bds bkb bkc bkk bkn bko bks bnb bnc bnd bnk bnn bno bns bob boc bod bok bon boo bos bsb bsc bsd bsk bsn bso bss c-- cbb cbc cbd cbk cbn cbo cbs ccb ccc ccd cck ccn cco ccs cdb cdc cdd cdk cdn cdo cds ckb ckc ckd cko cks cn- cnb cnc cnd cnn cno cns co- cob coc cod cok con coo cos csb csc csd csk csn cso css dbb dbc dbd dbk dbn dbo dbs dcb dcc dcd dck dcn dco dcs ddb ddc ddd ddk ddn ddo dds dkb dkc dkk dko dks dnb dnc dnd dnk dnn dno dns dob doc dod dok don doo dos dsb dsc dsd dsk dsn dso dss kbb kbc kbd kbk kbn kbo kbs kcb kcc kcd kck kcn kcs kdb kdc kdk kdo kds kkb kkc kkk kkn kks kn- knc knd knk knn kno kob koc kod kok kon koo kos ksb ksc ksd ksk ksn kso kss nbb nbc nbd nbk nbn nbo nbs ncb ncc ncd nck ncn nco ncs ndb ndc ndd ndk ndn ndo nds nkc nkk nkn nko nks nnb nnc nnk nnn nno nns no- nob noc nod nok non noo nos nsb nsc nsd nsk nsn nso nss ob- obb obc obd obk obn obo obs oc- ocb occ ocd ock ocn oco ocs odb odc odd odn odo ods okb okc okd okk oko oks on- onb onc ond onk onn ono ons oo- oob ooc ood ook oon ooo oos os- osb osc osd osk osn oso oss sbb sbc sbd sbk sbn sbo sbs scb scc scd sck scn sco scs sdb sdc sdd sdk sdn sdo sds sk- skb skc skd skk sko sks snb snc snd snk snn sno sns sob soc sod sok son soo sos ss- ssb ssc ssd ssk ssn sso sss