c-- ccc ccf cco ccp ccr ccs cfc cff cfo cfp cfr cfs co- coc cof coo cop cor cos cpc cpf cpo cpp cpr cps crc crf cro crp crr crs csc csf cso csp csr css fcc fcf fco fcp fcr fcs ffc fff ffo ffp ffr ffs foc fof foo fop for fos fpc fpo fpp fpr fps frc frf fro frp frr frs fsc fsf fso fsp fsr fss oc- occ ocf oco ocp ocr ocs of- ofc off ofo ofp ofr ofs oo- ooc oof ooo oop oor oos op- opc opf opo opp opr ops or- orc orf oro orp orr ors os- osc osf oso osp osr oss p-p pcc pcf pco pcp pcr pcs pfc pff pfo pfp pfr pfs poc pof poo pop por pos ppc ppf ppo ppp ppr pps prc prf pro prp prr prs ps- psc psf pso psp psr pss rcc rcf rco rcp rcr rcs rfc rff rfo rfp rfr rfs roc rof roo rop ror ros rpc rpf rpo rpp rpr rps rrc rrf rrp rrr rrs rsc rsf rso rsp rsr rss scc scf sco scp scr scs sfc sff sfo sfp sfr sfs soc sof soo sop sor sos spc spf spo spp spr sps sr- src srf sro srp srr srs ss- ssc ssf sso ssp ssr sss