c-- ccc ccf cco ccp ccr ccs cct cfc cff cfo cfp cfr cfs cft co- coc cof coo cop cor cos cot cpc cpf cpo cpp cpr cps cpt crc crf cro crp crr crs crt csc csf cso csp csr css cst ctc ctf cto ctp ctr cts ctt fcc fcf fco fcp fcr fcs fct ffc fff ffo ffp ffr ffs fft foc fof foo fop for fos fot fpc fpo fpp fpr fps fpt frc frf fro frp frr frs frt fsc fsf fso fsp fsr fss fst ftc ftf fto ftp ftr fts ftt oc- occ ocf oco ocp ocr ocs oct of- ofc off ofo ofp ofr ofs oft oo- ooc oof ooo oop oor oos oot op- opc opf opo opp opr ops opt or- orc orf oro orp orr ors ort os- osc osf oso osp osr oss ost ot- otc otf oto otp otr ots ott p-p pcc pcf pco pcp pcr pcs pct pfc pff pfo pfp pfr pfs pft poc pof poo pop por pos pot ppc ppf ppo ppp ppr pps ppt prc prf pro prp prr prs prt ps- psc psf pso psp psr pss pst pt- ptc ptf pto ptp ptr pts ptt rcc rcf rco rcp rcr rcs rct rfc rff rfo rfp rfr rfs rft roc rof roo rop ror ros rot rpc rpf rpo rpp rpr rps rpt rrc rrf rrp rrr rrs rrt rsc rsf rso rsp rsr rss rst rtc rtf rto rtp rtr rts rtt scc scf sco scp scr scs sct sfc sff sfo sfp sfr sfs sft soc sof soo sop sor sos sot spc spf spo spp spr sps spt sr- src srf sro srp srr srs srt ss- ssc ssf sso ssp ssr sss sst stc stf sto stp str sts stt tcc tcf tco tcp tcr tcs tct tfc tff tfo tfp tfr tfs tft to- toc tof too top tor tos tot tpc tpf tpo tpp tpr tps tpt trc trf tro trp trr trs trt tsc tsf tso tsp tsr tss tst ttc ttf tto ttp ttr tts ttt