cccc cccf ccfc ccff ccnc ccnf ccnr ccoc ccrc ccrf cfcf cfcn cfco cffr cfnr cfor cfrn cnco cnrc cnrr coco cofc coff con- conc conf conn cono coof coon cor- corc corf corn coro corr crcc crcr crfc croc cron croo cror fccf ffcc ffff ffrr foco fofo fono foof foon for- forn foro forr frcc frcn frfc fron nccc nccf nccn nccr ncfc ncnc ncoc ncor ncrc nfff nfon nnnn noco non- nonn nono noo- noon nooo noor nor- norc norf norn noro norr nrfc nroc nron nrrc occc occn ocon ocro ocrr ofcr off- offc offo offr ofno ofor onc- oncf onco onno onon onor oocr ooff oooo orco orff ornc orno oro- orof oron oror orro rccc rcfc rcnr rcon rffc rnco rocc roco rofc roff rofo ronc rono roof roon roor rorc roro rrfc rrrr