c-- ccc ccn cco ccr ccs cn- cnc cnn cno cnr cns co- coc con coo cor cos crc crn cro crr crs csc csn cso csr css ncc ncn nco ncr ncs nnc nnn nno nns no- noc non noo nor nos nrc nrn nro nrr nrs nsc nsn nso nsr nss oc- occ ocn oco ocr ocs on- onc onn ono onr ons oo- ooc oon ooo oor oos or- orc orn oro orr ors os- osc osn oso osr oss rcc rcn rco rcr rcs rnc rnn rno rnr rns roc ron roo ror ros rrc rrn rrr rrs rsc rsn rso rsr rss scc scn sco scr scs snc snn sno snr sns soc son soo sor sos sr- src srn sro srr srs ss- ssc ssn sso ssr sss