c-- ccc ccd ccf cco ccp ccr cdc cdd cdf cdo cdp cdr cfc cfd cff cfo cfp cfr co- coc cod cof coo cop cor cpc cpd cpf cpo cpp cpr crc crd crf cro crp crr dcc dcd dcf dco dcp dcr ddc ddd ddf ddo ddp ddr dfc dfd dff dfo dfp dfr doc dod dof doo dop dor dpc dpd dpf dpo dpp dpr drc drd dro drp drr fcc fcd fcf fco fcp fcr fdc fdd fdf fdo fdp fdr ffc ffd fff ffo ffp ffr foc fof foo fop for fpc fpd fpo fpp fpr frc frd frf fro frp frr oc- occ ocd ocf oco ocp ocr odc odd odf odo odp odr of- ofc ofd off ofo ofp ofr oo- ooc ood oof ooo oop oor op- opc opd opf opo opp opr or- orc ord orf oro orp orr p-p pcc pcd pcf pco pcp pcr pdc pdd pdf pdo pdp pdr pfc pfd pff pfo pfp pfr poc pod pof poo pop por ppc ppd ppf ppo ppp ppr prc prd prf pro prp prr rcc rcd rcf rco rcp rcr rdc rdd rdf rdo rdp rdr rfc rfd rff rfo rfp rfr roc rod rof roo rop ror rpc rpd rpf rpo rpp rpr rrc rrd rrf rrp rrr