-er a-a a-c aaa aac aae aak aan aap aar ac- aca acc ace ack acn acp acr aea aec aee aek aen aep aer aka akc ake akk akn akp akr an- ana anc ane ank ann anp anr ap- apa apc ape apk apn app apr ar- ara arc are ark arn arp arr c-- caa cac cae cak can cap car cca ccc cce cck ccn ccp ccr ce- cea cec cee cek cen cep cer cka ckc cn- cna cnc cne cnn cnp cnr cpa cpc cpe cpk cpn cpp cpr cra crc cre crk crn crp crr eaa eac eae eak ean eap ear ec- eca ecc ece eck ecn ecr eea eec eee eek een eep eer eka ekc eke ekp ekr en- ena enc ene enk enn enp enr ep- epa epc epe epn epp epr era erc ere erk ern erp err ka- kaa kac kae kak kan kap kar kca kcc kce kck kcn kcp kcr ke- kea kec kee kek ken kep ker kkc kke kkk kkn kkp kkr kn- kna knc kne knk knn knp knr kpa kpc kpe kpk kpn kpp kpr kra krc krk krn krp krr naa nac nae nak nan nap nar nca ncc nce nck ncn ncp ncr ne- nea nec nee nek nen nep ner nka nkc nke nkk nkn nkp nkr nna nnc nne nnk nnn nnp npa npc npe npn npp npr nra nrc nre nrk nrn nrp nrr p-p paa pac pae pak pan pap par pca pcc pce pck pcn pcp pcr pea pec pee pek pen pep per pka pkc pke pkn pkp pkr pn- pna pnc pne pnk pnn pnp pnr ppa ppc ppe ppk ppn ppp ppr pra prc pre prk prn prp prr ra- raa rac rae rak ran rap rar rca rcc rce rcn rcp rcr re- rea rec ree rek ren rep rer rkc rke rkk rkp rna rnc rnn rnp rnr rpa rpc rpe rpk rpn rpp rpr rra rrc rrk rrn rrp rrr