c-- ccc ccd cco ccr ccs cct cdc cdd cdo cdr cds cdt co- coc cod coo cor cos cot crc crd cro crr crs crt csc csd cso csr css cst ctc ctd cto ctr cts ctt dcc dcd dco dcr dcs dct ddc ddd ddo ddr dds ddt doc dod doo dor dos dot drc drd dro drr drs drt dsc dsd dso dsr dss dst dtc dtd dto dtr dts dtt oc- occ ocd oco ocr ocs oct odc odd odo odr ods odt oo- ooc ood ooo oor oos oot or- orc ord oro orr ors ort os- osc osd oso osr oss ost ot- otc otd oto otr ots ott rcc rcd rco rcr rcs rct rdc rdd rdo rdr rds rdt roc rod roo ror ros rot rrc rrd rrr rrs rrt rsc rsd rso rsr rss rst rtc rtd rto rtr rts rtt scc scd sco scr scs sct sdc sdd sdo sdr sds sdt soc sod soo sor sos sot sr- src srd sro srr srs srt ss- ssc ssd sso ssr sss sst stc std sto str sts stt tcc tcd tco tcr tcs tct tdc tdd tdo tdr tds tdt to- toc tod too tor tos tot trc trd tro trr trs trt tsc tsd tso tsr tss tst ttc ttd tto ttr tts ttt