-er a-a a-c aaa aac aae aao aap aar aav ac- aca acc ace aco acp acr acv aea aec aee aeo aep aer aev aoa aoc aoe aoo aop aor aov ap- apa apc ape apo app apr apv ar- ara arc are aro arp arr arv av- ava avc ave avo avp avr c-- caa cac cae cao cap car cav cca ccc cce cco ccp ccr ccv ce- cea cec cee ceo cep cer cev co- coa coc coe coo cop cor cov cpa cpc cpe cpo cpp cpr cpv cra crc cre cro crp crr crv cva cvc cve cvo cvp cvr cvv eaa eac eae eao eap ear eav ec- eca ecc ece eco ecr ecv eea eec eee eeo eep eer eev eo- eoa eoc eoe eoo eop eor ep- epa epc epe epo epp epr era erc ere ero erp err erv eva evc eve evo evp evr evv oaa oac oae oao oap oar oav oc- oca occ oco ocp ocr ocv oea oec oee oeo oep oer oo- ooa ooc ooo oop oor oov op- opa opc ope opo opp opr opv or- ora orc ore oro orp orr orv ov- ova ovc ove ovo ovp ovv p-p paa pac pae pao pap par pav pca pcc pce pco pcp pcr pcv pea pec pee peo pep per pev poa poc poe poo pop por pov ppa ppc ppe ppo ppp ppr ppv pra prc pre pro prp prr prv pva pvc pve pvo pvp pvr pvv ra- raa rac rae rao rap rar rav rca rcc rce rco rcp rcr rcv re- rea rec ree reo rep rer rev roa roc roe roo rop ror rov rpa rpc rpe rpo rpp rpr rpv rra rrc rrp rrr rva rvc rve rvo rvp rvr rvv v-a v-e vaa vac vae vao vap var vav vca vcc vce vco vcp vcr vea vec vee veo vep ver voa voc voe voo vop vor vov vpa vpc vpe vpo vpp vpr vra vrc vre vrp vrr vva vvc vvo vvr vvv