-er b-u bbb bbe bbk bbn bbo bbr bbu be- beb bee bek ben beo ber beu bkb bke bkk bkn bko bkr bnb bne bnk bnn bno bnr bnu bob boe bok bon boo bor bou brb bre brk brn bro brr bru bub bue buk bun buo bur buu ebb ebe ebk ebn ebo ebr ebu eeb eee eek een eeo eer ekb eke eko ekr eku en- enb ene enk enn eno enr enu eo- eob eoe eok eon eoo eor eou erb ere erk ern ero err eru eu- eub eue eun eur kbb kbe kbk kbn kbo kbr kbu ke- keb kee kek ken keo ker kkb kke kkk kkn kkr kku kn- kne knk knn kno knr knu kob koe kok kon koo kor kou krk krn kro krr kru kub kue kuk kun kur kuu nbb nbe nbk nbn nbo nbr nbu ne- neb nee nek nen neo ner neu nke nkk nkn nko nkr nku nnb nne nnk nnn nno nnu no- nob noe nok non noo nor nou nrb nre nrk nrn nro nrr nru nub nue nuk nun nuo nur nuu ob- obb obe obk obn obo obr obu oeb oee oen oeo oer okb oke okk oko okr oku on- onb one onk onn ono onr onu oo- oob ook oon ooo oor or- orb ore ork orn oro orr oru ou- oue ouk oun ouo our rbb rbe rbk rbn rbo rbr rbu re- reb ree rek ren reo rer reu rkb rke rkk rko rku rnb rnn rno rnr rnu rob roe rok ron roo ror rou rrb rrk rrn rrr rru rub rue ruk run ruo rur ruu ubb ube ubk ubn ubo ubr ubu ueb uee uen uer ukb uke ukk ukn ukr uku un- unb une unk unn uno unr unu uob uoe uok uon uoo uor ur- urb ure urk urn uro urr uru uue uun uur uuu