-er b-u bbb bbc bbe bbn bbr bbu bcb bcc bce bcn bcr bcu be- beb bec bee ben ber beu bnb bnc bne bnn bnr bnu brb bre brn brr bru bub buc bue bun bur buu c-- cbb cbc cbe cbn cbr cbu ccb ccc cce ccn ccr ccu ce- ceb cec cee cen cer ceu cn- cnb cnc cne cnn cnr cnu crb crc cre crn crr cru cub cuc cue cun cur cuu ebb ebc ebe ebn ebr ebu ec- ecb ecc ece ecn ecr ecu eeb eec eee een eer en- enb enc ene enn enr enu erb erc ere ern err eru eu- eub euc eue eun eur nbb nbc nbe nbn nbr nbu ncb ncc nce ncn ncr ncu ne- neb nec nee nen ner neu nnb nnc nne nnn nnu nrb nrc nre nrn nrr nru nub nuc nue nun nur nuu rbb rbc rbe rbn rbr rbu rcb rcc rce rcn rcr rcu re- reb rec ree ren rer reu rnb rnc rnn rnr rnu rrb rrc rrn rrr rru rub ruc rue run rur ruu ubb ubc ube ubn ubr ubu ucb ucc uce ucn ucr ucu ueb uec uee uen uer un- unb unc une unn unr unu ur- urb urc ure urn urr uru uuc uue uun uur uuu