-er bbb bbe bbk bbn bbo bbr bbs be- beb bee bek ben beo ber bes bkb bke bkk bkn bko bkr bks bnb bne bnk bnn bno bnr bns bob boe bok bon boo bor bos brb bre brk brn bro brr brs bsb bse bsk bsn bso bsr bss ebb ebe ebk ebn ebo ebr ebs eeb eee eek een eeo eer ees ekb eke eko ekr eks en- enb ene enk enn eno enr ens eo- eob eoe eok eon eoo eor eos erb ere erk ern ero err ers es- esb ese esk esn eso esr ess kbb kbe kbk kbn kbo kbr kbs ke- keb kee kek ken keo ker kes kkb kke kkk kkn kkr kks kn- kne knk knn kno knr kob koe kok kon koo kor kos krk krn kro krr krs ksb kse ksk ksn kso ksr kss nbb nbe nbk nbn nbo nbr nbs ne- neb nee nek nen neo ner nes nke nkk nkn nko nkr nks nnb nne nnk nnn nno nns no- nob noe nok non noo nor nos nrb nre nrk nrn nro nrr nrs nsb nse nsk nsn nso nsr nss ob- obb obe obk obn obo obr obs oeb oee oen oeo oer oes okb oke okk oko okr oks on- onb one onk onn ono onr ons oo- oob ook oon ooo oor oos or- orb ore ork orn oro orr ors os- osb ose osk osn oso osr oss rbb rbe rbk rbn rbo rbr rbs re- reb ree rek ren reo rer res rkb rke rkk rko rks rnb rnn rno rnr rns rob roe rok ron roo ror ros rrb rrk rrn rrr rrs rsb rse rsk rsn rso rsr rss sbb sbe sbk sbn sbo sbr sbs se- seb see sek sen seo ser ses sk- skb ske skk sko skr sks snb sne snk snn sno snr sns sob soe sok son soo sor sos sr- srb sre srk srn sro srr srs ss- ssb sse ssk ssn sso ssr sss