c-- ccc ccf cco ccr ccs cct cfc cff cfo cfr cfs cft co- coc cof coo cor cos cot crc crf cro crr crs crt csc csf cso csr css cst ctc ctf cto ctr cts ctt fcc fcf fco fcr fcs fct ffc fff ffo ffr ffs fft foc fof foo for fos fot frc frf fro frr frs frt fsc fsf fso fsr fss fst ftc ftf fto ftr fts ftt oc- occ ocf oco ocr ocs oct of- ofc off ofo ofr ofs oft oo- ooc oof ooo oor oos oot or- orc orf oro orr ors ort os- osc osf oso osr oss ost ot- otc otf oto otr ots ott rcc rcf rco rcr rcs rct rfc rff rfo rfr rfs rft roc rof roo ror ros rot rrc rrf rrr rrs rrt rsc rsf rso rsr rss rst rtc rtf rto rtr rts rtt scc scf sco scr scs sct sfc sff sfo sfr sfs sft soc sof soo sor sos sot sr- src srf sro srr srs srt ss- ssc ssf sso ssr sss sst stc stf sto str sts stt tcc tcf tco tcr tcs tct tfc tff tfo tfr tfs tft to- toc tof too tor tos tot trc trf tro trr trs trt tsc tsf tso tsr tss tst ttc ttf tto ttr tts ttt