c-- ccc ccd cce cck cco cdc cdd cde cdk cdo ce- cec ced cee cek ceo ckc ckd cko co- coc cod coe cok coo dcc dcd dce dck dco ddc ddd dde ddk ddo de- dec ded dee dek deo dkc dke dkk dko doc dod doe dok doo ec- ecc ecd ece eck eco ed- edc edd ede edk edo eec eed eee eek eeo ekc ekd eke eko eo- eoc eod eoe eok eoo kcc kcd kce kck kdc kde kdk kdo ke- kec ked kee kek keo kkc kke kkk koc kod koe kok koo oc- occ ocd ock oco odc odd ode odo oec oed oee oeo okc okd oke okk oko oo- ooc ood ook ooo