bbb bbc bbd bbe bbn bcb bcc bcd bce bcn bdb bdc bdd bde be- beb bec bed bee ben bnb bnc bnd bne bnn c-- cbb cbc cbd cbe cbn ccb ccc ccd cce ccn cdb cdc cdd cde cdn ce- ceb cec ced cee cen cn- cnb cnc cnd cne cnn dbb dbc dbd dbe dbn dcb dcc dcd dce dcn ddb ddc ddd dde ddn de- deb dec ded dee den dnb dnc dnd dne dnn ebb ebc ebd ebe ebn ec- ecb ecc ecd ece ecn ed- edb edc edd ede edn eeb eec eed eee een en- enb enc end ene enn nbb nbc nbd nbe nbn ncb ncc ncd nce ncn ndb ndc ndd nde ndn ne- neb nec ned nee nen nnb nnc nne nnn