a-a a-c aaa aac aae aaf aak aap ac- aca acc ace acf ack acp aea aec aee aef aek aep af- afa afc afe aff afk afp aka akc ake akk akp ap- apa apc ape apf apk app c-- caa cac cae caf cak cap cca ccc cce ccf cck ccp ce- cea cec cee cef cek cep cfa cfc cfe cff cfk cfp cka ckc cpa cpc cpe cpf cpk cpp eaa eac eae eaf eak eap ec- eca ecc ece ecf eck eea eec eee eef eek eep ef- efa efc efe eff efp eka ekc eke ekf ekp ep- epa epc epe epf epp faa fac fae faf fak fap fca fcc fce fcf fck fcp fea fec fee fef fek fep ffa ffc ffe fff ffk ffp fka fkc fkf fkk fkp fpa fpc fpe fpk fpp ka- kaa kac kae kaf kak kap kca kcc kce kck kcp ke- kea kec kee kef kek kep kfa kfc kff kkc kke kkk kkp kpa kpc kpe kpf kpk kpp p-p paa pac pae paf pak pap pca pcc pce pcf pck pcp pea pec pee pef pek pep pfa pfc pfe pff pfk pfp pka pkc pke pkf pkp ppa ppc ppe ppf ppk ppp