bbb bbe bbf bbk bbn bbo be- beb bee bef bek ben beo bfb bfe bff bfn bfo bkb bke bkf bkk bkn bko bnb bne bnf bnk bnn bno bob boe bof bok bon boo ebb ebe ebf ebk ebn ebo eeb eee eef eek een eeo ef- efb efe eff efo ekb eke ekf eko en- enb ene enf enk enn eno eo- eob eoe eof eok eon eoo fbb fbe fbf fbk fbn fbo feb fee fef fek fen feo ffe fff ffk ffn ffo fkb fkf fkk fnb fne fnf fnk fnn fob foe fof fok fon foo kbb kbe kbf kbk kbn kbo ke- keb kee kef kek ken keo kff kfo kkb kke kkk kkn kn- kne knf knk knn kno kob koe kof kok kon koo nbb nbe nbf nbk nbn nbo ne- neb nee nef nek nen neo nfb nfe nff nfk nfn nfo nke nkf nkk nkn nko nnb nne nnf nnk nnn nno no- nob noe nof nok non noo ob- obb obe obf obk obn obo oeb oee oef oen oeo of- ofb ofe off ofn ofo okb oke okk oko on- onb one onf onk onn ono oo- oob oof ook oon ooo