c-- ccc ccd ccn cco cct cdc cdd cdn cdo cdt cn- cnc cnd cnn cno cnt co- coc cod con coo cot ctc ctd ctn cto ctt dcc dcd dcn dco dct ddc ddd ddn ddo ddt dnc dnd dnn dno dnt doc dod don doo dot dtc dtd dtn dto dtt ncc ncd ncn nco nct ndc ndd ndn ndo ndt nnc nnn nno nnt no- noc nod non noo not ntc ntd ntn nto ntt oc- occ ocd ocn oco oct odc odd odn odo odt on- onc ond onn ono ont oo- ooc ood oon ooo oot ot- otc otd otn oto ott tcc tcd tcn tco tct tdc tdd tdn tdo tdt tnc tnd tnn tno tnt to- toc tod ton too tot ttc ttd ttn tto ttt