-er b-u bbb bbc bbe bbn bbo bbr bbu bcb bcc bce bcn bco bcr bcu be- beb bec bee ben beo ber beu bnb bnc bne bnn bno bnr bnu bob boc boe bon boo bor bou brb bre brn bro brr bru bub buc bue bun buo bur buu c-- cbb cbc cbe cbn cbo cbr cbu ccb ccc cce ccn cco ccr ccu ce- ceb cec cee cen ceo cer ceu cn- cnb cnc cne cnn cno cnr cnu co- cob coc coe con coo cor cou crb crc cre crn cro crr cru cub cuc cue cun cuo cur cuu ebb ebc ebe ebn ebo ebr ebu ec- ecb ecc ece ecn eco ecr ecu eeb eec eee een eeo eer en- enb enc ene enn eno enr enu eo- eob eoc eoe eon eoo eor eou erb erc ere ern ero err eru eu- eub euc eue eun eur nbb nbc nbe nbn nbo nbr nbu ncb ncc nce ncn nco ncr ncu ne- neb nec nee nen neo ner neu nnb nnc nne nnn nno nnu no- nob noc noe non noo nor nou nrb nrc nre nrn nro nrr nru nub nuc nue nun nuo nur nuu ob- obb obc obe obn obo obr obu oc- ocb occ ocn oco ocr ocu oeb oec oee oen oeo oer on- onb onc one onn ono onr onu oo- oob ooc oon ooo oor or- orb orc ore orn oro orr oru ou- ouc oue oun ouo our rbb rbc rbe rbn rbo rbr rbu rcb rcc rce rcn rco rcr rcu re- reb rec ree ren reo rer reu rnb rnc rnn rno rnr rnu rob roc roe ron roo ror rou rrb rrc rrn rrr rru rub ruc rue run ruo rur ruu ubb ubc ube ubn ubo ubr ubu ucb ucc uce ucn uco ucr ucu ueb uec uee uen uer un- unb unc une unn uno unr unu uob uoc uoe uon uoo uor ur- urb urc ure urn uro urr uru uuc uue uun uur uuu