-er bbb bbc bbd bbe bbn bbr bcb bcc bcd bce bcn bcr bdb bdc bdd bde bdr be- beb bec bed bee ben ber bnb bnc bnd bne bnn bnr brb brd bre brn brr c-- cbb cbc cbd cbe cbn cbr ccb ccc ccd cce ccn ccr cdb cdc cdd cde cdn cdr ce- ceb cec ced cee cen cer cn- cnb cnc cnd cne cnn cnr crb crc crd cre crn crr dbb dbc dbd dbe dbn dbr dcb dcc dcd dce dcn dcr ddb ddc ddd dde ddn ddr de- deb dec ded dee den der dnb dnc dnd dne dnn dnr drb drc drd dre drn drr ebb ebc ebd ebe ebn ebr ec- ecb ecc ecd ece ecn ecr ed- edb edc edd ede edn edr eeb eec eed eee een eer en- enb enc end ene enn enr erb erc erd ere ern err nbb nbc nbd nbe nbn nbr ncb ncc ncd nce ncn ncr ndb ndc ndd nde ndn ndr ne- neb nec ned nee nen ner nnb nnc nne nnn nrb nrc nrd nre nrn nrr rbb rbc rbd rbe rbn rbr rcb rcc rcd rce rcn rcr rdb rdc rdd rde rdn rdr re- reb rec red ree ren rer rnb rnc rnd rnn rnr rrb rrc rrd rrn rrr