bbb bbc bbd bbk bbn bbo bbr bcb bcc bcd bck bcn bco bcr bdb bdc bdd bdk bdo bdr bkb bkc bkk bkn bko bkr bnb bnc bnd bnk bnn bno bnr bob boc bod bok bon boo bor brb brd brk brn bro brr c-- cbb cbc cbd cbk cbn cbo cbr ccb ccc ccd cck ccn cco ccr cdb cdc cdd cdk cdn cdo cdr ckb ckc ckd cko cn- cnb cnc cnd cnn cno cnr co- cob coc cod cok con coo cor crb crc crd crk crn cro crr dbb dbc dbd dbk dbn dbo dbr dcb dcc dcd dck dcn dco dcr ddb ddc ddd ddk ddn ddo ddr dkb dkc dkk dko dkr dnb dnc dnd dnk dnn dno dnr dob doc dod dok don doo dor drb drc drd drk drn dro drr kbb kbc kbd kbk kbn kbo kbr kcb kcc kcd kck kcn kcr kdb kdc kdk kdo kdr kkb kkc kkk kkn kkr kn- knc knd knk knn kno knr kob koc kod kok kon koo kor krc krd krk krn kro krr nbb nbc nbd nbk nbn nbo nbr ncb ncc ncd nck ncn nco ncr ndb ndc ndd ndk ndn ndo ndr nkc nkk nkn nko nkr nnb nnc nnk nnn nno no- nob noc nod nok non noo nor nrb nrc nrd nrk nrn nro nrr ob- obb obc obd obk obn obo obr oc- ocb occ ocd ock ocn oco ocr odb odc odd odn odo odr okb okc okd okk oko okr on- onb onc ond onk onn ono onr oo- oob ooc ood ook oon ooo oor or- orb orc ord ork orn oro orr rbb rbc rbd rbk rbn rbo rbr rcb rcc rcd rcn rco rcr rdb rdc rdd rdn rdo rdr rkb rkc rkk rko rnb rnc rnd rnn rno rnr rob roc rod rok ron roo ror rrb rrc rrd rrk rrn rrr