-er a-a a-c aaa aac aae aao aar aav ac- aca acc ace aco acr acv aea aec aee aeo aer aev aoa aoc aoe aoo aor aov ar- ara arc are aro arr arv av- ava avc ave avo avr c-- caa cac cae cao car cav cca ccc cce cco ccr ccv ce- cea cec cee ceo cer cev co- coa coc coe coo cor cov cra crc cre cro crr crv cva cvc cve cvo cvr cvv eaa eac eae eao ear eav ec- eca ecc ece eco ecr ecv eea eec eee eeo eer eev eo- eoa eoc eoe eoo eor era erc ere ero err erv eva evc eve evo evr evv oaa oac oae oao oar oav oc- oca occ oco ocr ocv oea oec oee oeo oer oo- ooa ooc ooo oor oov or- ora orc ore oro orr orv ov- ova ovc ove ovo ovv ra- raa rac rae rao rar rav rca rcc rce rco rcr rcv re- rea rec ree reo rer rev roa roc roe roo ror rov rra rrc rrr rva rvc rve rvo rvr rvv v-a v-e vaa vac vae vao var vav vca vcc vce vco vcr vea vec vee veo ver voa voc voe voo vor vov vra vrc vre vrr vva vvc vvo vvr vvv