-er bbb bbc bbd bbe bbk bbn bbo bbr bcb bcc bcd bce bck bcn bco bcr bdb bdc bdd bde bdk bdo bdr be- beb bec bed bee bek ben beo ber bkb bkc bke bkk bkn bko bkr bnb bnc bnd bne bnk bnn bno bnr bob boc bod boe bok bon boo bor brb brd bre brk brn bro brr c-- cbb cbc cbd cbe cbk cbn cbo cbr ccb ccc ccd cce cck ccn cco ccr cdb cdc cdd cde cdk cdn cdo cdr ce- ceb cec ced cee cek cen ceo cer ckb ckc ckd cko cn- cnb cnc cnd cne cnn cno cnr co- cob coc cod coe cok con coo cor crb crc crd cre crk crn cro crr dbb dbc dbd dbe dbk dbn dbo dbr dcb dcc dcd dce dck dcn dco dcr ddb ddc ddd dde ddk ddn ddo ddr de- deb dec ded dee dek den deo der dkb dkc dke dkk dko dkr dnb dnc dnd dne dnk dnn dno dnr dob doc dod doe dok don doo dor drb drc drd dre drk drn dro drr ebb ebc ebd ebe ebk ebn ebo ebr ec- ecb ecc ecd ece eck ecn eco ecr ed- edb edc edd ede edk edn edo edr eeb eec eed eee eek een eeo eer ekb ekc ekd eke eko ekr en- enb enc end ene enk enn eno enr eo- eob eoc eod eoe eok eon eoo eor erb erc erd ere erk ern ero err kbb kbc kbd kbe kbk kbn kbo kbr kcb kcc kcd kce kck kcn kcr kdb kdc kde kdk kdo kdr ke- keb kec ked kee kek ken keo ker kkb kkc kke kkk kkn kkr kn- knc knd kne knk knn kno knr kob koc kod koe kok kon koo kor krc krd krk krn kro krr nbb nbc nbd nbe nbk nbn nbo nbr ncb ncc ncd nce nck ncn nco ncr ndb ndc ndd nde ndk ndn ndo ndr ne- neb nec ned nee nek nen neo ner nkc nke nkk nkn nko nkr nnb nnc nne nnk nnn nno no- nob noc nod noe nok non noo nor nrb nrc nrd nre nrk nrn nro nrr ob- obb obc obd obe obk obn obo obr oc- ocb occ ocd ock ocn oco ocr odb odc odd ode odn odo odr oeb oec oed oee oen oeo oer okb okc okd oke okk oko okr on- onb onc ond one onk onn ono onr oo- oob ooc ood ook oon ooo oor or- orb orc ord ore ork orn oro orr rbb rbc rbd rbe rbk rbn rbo rbr rcb rcc rcd rce rcn rco rcr rdb rdc rdd rde rdn rdo rdr re- reb rec red ree rek ren reo rer rkb rkc rke rkk rko rnb rnc rnd rnn rno rnr rob roc rod roe rok ron roo ror rrb rrc rrd rrk rrn rrr