c-- ccc cck cco ccp ccr ckc cko co- coc cok coo cop cor cpc cpk cpo cpp cpr crc crk cro crp crr kcc kck kcp kcr kkc kkk kkp kkr koc kok koo kop kor kpc kpk kpo kpp kpr krc krk kro krp krr oc- occ ock oco ocp ocr okc okk oko okp okr oo- ooc ook ooo oop oor op- opc opk opo opp opr or- orc ork oro orp orr p-p pcc pck pco pcp pcr pkc pko pkp pkr poc pok poo pop por ppc ppk ppo ppp ppr prc prk pro prp prr rcc rco rcp rcr rkc rkk rko rkp roc rok roo rop ror rpc rpk rpo rpp rpr rrc rrk rrp rrr