a-a a-c aaa aac aae aak aao aap ac- aca acc ace ack aco acp aea aec aee aek aeo aep aka akc ake akk ako akp aoa aoc aoe aok aoo aop ap- apa apc ape apk apo app c-- caa cac cae cak cao cap cca ccc cce cck cco ccp ce- cea cec cee cek ceo cep cka ckc cko co- coa coc coe cok coo cop cpa cpc cpe cpk cpo cpp eaa eac eae eak eao eap ec- eca ecc ece eck eco eea eec eee eek eeo eep eka ekc eke eko ekp eo- eoa eoc eoe eok eoo eop ep- epa epc epe epo epp ka- kaa kac kae kak kao kap kca kcc kce kck kcp ke- kea kec kee kek keo kep kkc kke kkk kkp koa koc koe kok koo kop kpa kpc kpe kpk kpo kpp oaa oac oae oak oao oap oc- oca occ ock oco ocp oea oec oee oeo oep oka okc oke okk oko okp oo- ooa ooc ook ooo oop op- opa opc ope opk opo opp p-p paa pac pae pak pao pap pca pcc pce pck pco pcp pea pec pee pek peo pep pka pkc pke pko pkp poa poc poe pok poo pop ppa ppc ppe ppk ppo ppp