-er bbb bbc bbe bbh bbk bbn bbo bbr bcb bcc bce bch bck bcn bco bcr be- beb bec bee beh bek ben beo ber bhb bhc bhe bhh bhk bho bhr bkb bkc bke bkk bkn bko bkr bnb bnc bne bnk bnn bno bnr bob boc boe boh bok bon boo bor brb bre brh brk brn bro brr c-- cbb cbc cbe cbh cbk cbn cbo cbr ccb ccc cce cch cck ccn cco ccr ce- ceb cec cee ceh cek cen ceo cer ch- chb chc che chh chk chn cho chr ckb ckc ckh cko cn- cnb cnc cne cnh cnn cno cnr co- cob coc coe coh cok con coo cor crb crc cre crh crk crn cro crr ebb ebc ebe ebh ebk ebn ebo ebr ec- ecb ecc ece ech eck ecn eco ecr eeb eec eee eek een eeo eer ehb ehc ehe ehh ehn eho ehr ekb ekc eke ekh eko ekr en- enb enc ene enh enk enn eno enr eo- eob eoc eoe eoh eok eon eoo eor erb erc ere erh erk ern ero err hbb hbc hbe hbh hbk hbn hbo hbr hcb hcc hce hch hck hcn hco hcr he- heb hec hee heh hek hen heo her hhb hhc hhe hhh hhk hhn hho hhr hkb hkh hkk hkn hko hkr hnb hnc hne hnh hnk hnn hno hob hoc hoe hoh hok hon hoo hor hr- hrb hrc hre hrh hrk hrn hro hrr kbb kbc kbe kbh kbk kbn kbo kbr kcb kcc kce kch kck kcn kcr ke- keb kec kee keh kek ken keo ker khe khh khk khn kho khr kkb kkc kke kkh kkk kkn kkr kn- knc kne knk knn kno knr kob koc koe koh kok kon koo kor krc krk krn kro krr nbb nbc nbe nbk nbn nbo nbr ncb ncc nce nch nck ncn nco ncr ne- neb nec nee neh nek nen neo ner nhb nhc nhe nhh nhk nhn nhr nkc nke nkk nkn nko nkr nnb nnc nne nnh nnk nnn nno no- nob noc noe noh nok non noo nor nrb nrc nre nrk nrn nro nrr ob- obb obc obe obh obk obn obo obr oc- ocb occ och ock ocn oco ocr oeb oec oee oeh oen oeo oer ohc ohe ohh ohn oho ohr okb okc oke okk oko okr on- onb onc one onh onk onn ono onr oo- oob ooc ooh ook oon ooo oor or- orb orc ore orh ork orn oro orr rbb rbc rbe rbh rbk rbn rbo rbr rcb rcc rce rch rcn rco rcr re- reb rec ree reh rek ren reo rer rh- rhb rhc rhe rhh rhn rho rhr rkb rkc rke rkk rko rnb rnc rnh rnn rno rnr rob roc roe roh rok ron roo ror rrb rrc rrh rrk rrn rrr