a-a a-c aaa aac aak aao aap ac- aca acc ack aco acp aka akc akk ako akp aoa aoc aok aoo aop ap- apa apc apk apo app c-- caa cac cak cao cap cca ccc cck cco ccp cka ckc cko co- coa coc cok coo cop cpa cpc cpk cpo cpp ka- kaa kac kak kao kap kca kcc kck kcp kkc kkk kkp koa koc kok koo kop kpa kpc kpk kpo kpp oaa oac oak oao oap oc- oca occ ock oco ocp oka okc okk oko okp oo- ooa ooc ook ooo oop op- opa opc opk opo opp p-p paa pac pak pao pap pca pcc pck pco pcp pka pkc pko pkp poa poc pok poo pop ppa ppc ppk ppo ppp