-er a-a a-c aaa aac aae aan aao aar ac- aca acc ace acn aco acr aea aec aee aen aeo aer an- ana anc ane ann ano anr aoa aoc aoe aon aoo aor ar- ara arc are arn aro arr c-- caa cac cae can cao car cca ccc cce ccn cco ccr ce- cea cec cee cen ceo cer cn- cna cnc cne cnn cno cnr co- coa coc coe con coo cor cra crc cre crn cro crr eaa eac eae ean eao ear ec- eca ecc ece ecn eco ecr eea eec eee een eeo eer en- ena enc ene enn eno enr eo- eoa eoc eoe eon eoo eor era erc ere ern ero err naa nac nae nan nao nar nca ncc nce ncn nco ncr ne- nea nec nee nen neo ner nna nnc nne nnn nno no- noa noc noe non noo nor nra nrc nre nrn nro nrr oaa oac oae oan oao oar oc- oca occ ocn oco ocr oea oec oee oen oeo oer on- ona onc one onn ono onr oo- ooa ooc oon ooo oor or- ora orc ore orn oro orr ra- raa rac rae ran rao rar rca rcc rce rcn rco rcr re- rea rec ree ren reo rer rna rnc rnn rno rnr roa roc roe ron roo ror rra rrc rrn rrr