-er b-u bbb bbe bbn bbo bbr bbu bbx be- beb bee ben beo ber beu bex bnb bne bnn bno bnr bnu bnx bob boe bon boo bor bou box brb bre brn bro brr bru brx bub bue bun buo bur buu bux bxb bxn bxo bxx ebb ebe ebn ebo ebr ebu ebx eeb eee een eeo eer eex en- enb ene enn eno enr enu eo- eob eoe eon eoo eor eou erb ere ern ero err eru eu- eub eue eun eur eux ex- exe exo exr exu exx nbb nbe nbn nbo nbr nbu nbx ne- neb nee nen neo ner neu nex nnb nne nnn nno nnu no- nob noe non noo nor nou nox nrb nre nrn nro nrr nru nrx nub nue nun nuo nur nuu nux ob- obb obe obn obo obr obu obx oeb oee oen oeo oer oex on- onb one onn ono onr onu onx oo- oob oon ooo oor oox or- orb ore orn oro orr oru orx ou- oue oun ouo our ox- oxb oxn oxo oxx rbb rbe rbn rbo rbr rbu rbx re- reb ree ren reo rer reu rex rnb rnn rno rnr rnu rob roe ron roo ror rou rox rrb rrn rrr rru rub rue run ruo rur ruu rux rxr ubb ube ubn ubo ubr ubu ubx ueb uee uen uer un- unb une unn uno unr unu unx uob uoe uon uoo uor uox ur- urb ure urn uro urr uru urx uue uun uur uuu uxb uxo uxr uxu xbe xbr xbx xee xen xer xeu xex xno xnu xon xoo xor xox xrx xue xun xxo xxx