-er bbb bbe bbn bbo bbr bbs be- beb bee ben beo ber bes bnb bne bnn bno bnr bns bob boe bon boo bor bos brb bre brn bro brr brs bsb bse bsn bso bsr bss ebb ebe ebn ebo ebr ebs eeb eee een eeo eer ees en- enb ene enn eno enr ens eo- eob eoe eon eoo eor eos erb ere ern ero err ers es- esb ese esn eso esr ess nbb nbe nbn nbo nbr nbs ne- neb nee nen neo ner nes nnb nne nnn nno nns no- nob noe non noo nor nos nrb nre nrn nro nrr nrs nsb nse nsn nso nsr nss ob- obb obe obn obo obr obs oeb oee oen oeo oer oes on- onb one onn ono onr ons oo- oob oon ooo oor oos or- orb ore orn oro orr ors os- osb ose osn oso osr oss rbb rbe rbn rbo rbr rbs re- reb ree ren reo rer res rnb rnn rno rnr rns rob roe ron roo ror ros rrb rrn rrr rrs rsb rse rsn rso rsr rss sbb sbe sbn sbo sbr sbs se- seb see sen seo ser ses snb sne snn sno snr sns sob soe son soo sor sos sr- srb sre srn sro srr srs ss- ssb sse ssn sso ssr sss