c-- ccc ccf ccn cco ccr ccs cfc cff cfn cfo cfr cfs cn- cnc cnf cnn cno cnr cns co- coc cof con coo cor cos crc crf crn cro crr crs csc csf csn cso csr css fcc fcf fcn fco fcr fcs ffc fff ffn ffo ffr ffs fnc fnf fnn fnr fns foc fof fon foo for fos frc frf frn fro frr frs fsc fsf fsn fso fsr fss ncc ncf ncn nco ncr ncs nfc nff nfn nfo nfr nfs nnc nnf nnn nno nns no- noc nof non noo nor nos nrc nrf nrn nro nrr nrs nsc nsf nsn nso nsr nss oc- occ ocf ocn oco ocr ocs of- ofc off ofn ofo ofr ofs on- onc onf onn ono onr ons oo- ooc oof oon ooo oor oos or- orc orf orn oro orr ors os- osc osf osn oso osr oss rcc rcf rcn rco rcr rcs rfc rff rfn rfo rfr rfs rnc rnn rno rnr rns roc rof ron roo ror ros rrc rrf rrn rrr rrs rsc rsf rsn rso rsr rss scc scf scn sco scr scs sfc sff sfn sfo sfr sfs snc snf snn sno snr sns soc sof son soo sor sos sr- src srf srn sro srr srs ss- ssc ssf ssn sso ssr sss