-er a-a a-c aaa aac aae aak aao aap aar aav ac- aca acc ace ack aco acp acr acv aea aec aee aek aeo aep aer aev aka akc ake akk ako akp akr akv aoa aoc aoe aok aoo aop aor aov ap- apa apc ape apk apo app apr apv ar- ara arc are ark aro arp arr arv av- ava avc ave avk avo avp avr c-- caa cac cae cak cao cap car cav cca ccc cce cck cco ccp ccr ccv ce- cea cec cee cek ceo cep cer cev cka ckc cko co- coa coc coe cok coo cop cor cov cpa cpc cpe cpk cpo cpp cpr cpv cra crc cre crk cro crp crr crv cva cvc cve cvk cvo cvp cvr cvv eaa eac eae eak eao eap ear eav ec- eca ecc ece eck eco ecr ecv eea eec eee eek eeo eep eer eev eka ekc eke eko ekp ekr ekv eo- eoa eoc eoe eok eoo eop eor ep- epa epc epe epo epp epr era erc ere erk ero erp err erv eva evc eve evo evp evr evv ka- kaa kac kae kak kao kap kar kav kca kcc kce kck kcp kcr ke- kea kec kee kek keo kep ker kev kkc kke kkk kkp kkr kkv koa koc koe kok koo kop kor kpa kpc kpe kpk kpo kpp kpr kpv kra krc krk kro krp krr krv kva kvk kvo kvp kvr kvv oaa oac oae oak oao oap oar oav oc- oca occ ock oco ocp ocr ocv oea oec oee oeo oep oer oka okc oke okk oko okp okr oo- ooa ooc ook ooo oop oor oov op- opa opc ope opk opo opp opr opv or- ora orc ore ork oro orp orr orv ov- ova ovc ove ovo ovp ovv p-p paa pac pae pak pao pap par pav pca pcc pce pck pco pcp pcr pcv pea pec pee pek peo pep per pev pka pkc pke pko pkp pkr poa poc poe pok poo pop por pov ppa ppc ppe ppk ppo ppp ppr ppv pra prc pre prk pro prp prr prv pva pvc pve pvk pvo pvp pvr pvv ra- raa rac rae rak rao rap rar rav rca rcc rce rco rcp rcr rcv re- rea rec ree rek reo rep rer rev rkc rke rkk rko rkp rkv roa roc roe rok roo rop ror rov rpa rpc rpe rpk rpo rpp rpr rpv rra rrc rrk rrp rrr rva rvc rve rvo rvp rvr rvv v-a v-e vaa vac vae vak vao vap var vav vca vcc vce vco vcp vcr vea vec vee vek veo vep ver vka vkp voa voc voe vok voo vop vor vov vpa vpc vpe vpk vpo vpp vpr vra vrc vre vrk vrp vrr vva vvc vvo vvr vvv