c-- ccc ccd ccm cco cct cdc cdd cdm cdo cdt cmc cmd cmm cmo cmt co- coc cod com coo cot ctc ctd ctm cto ctt dcc dcd dcm dco dct ddc ddd ddm ddo ddt dmc dmd dmm dmo dmt doc dod dom doo dot dtc dtd dtm dto dtt m-o mc- mcc mcd mcm mco mct mdc mdd mdm mdo mdt mmc mmd mmm mmo mmt moc mod mom moo mot mtc mtd mtm mto mtt oc- occ ocd ocm oco oct odc odd odm odo odt om- omc omd omm omo omt oo- ooc ood oom ooo oot ot- otc otd otm oto ott tcc tcd tcm tco tct tdc tdd tdm tdo tdt tmc tmd tmm tmo tmt to- toc tod tom too tot ttc ttd ttm tto ttt