a-a a-c aaa aac aan aao aar ac- aca acc acn aco acr an- ana anc ann ano anr aoa aoc aon aoo aor ar- ara arc arn aro arr c-- caa cac can cao car cca ccc ccn cco ccr cn- cna cnc cnn cno cnr co- coa coc con coo cor cra crc crn cro crr naa nac nan nao nar nca ncc ncn nco ncr nna nnc nnn nno no- noa noc non noo nor nra nrc nrn nro nrr oaa oac oan oao oar oc- oca occ ocn oco ocr on- ona onc onn ono onr oo- ooa ooc oon ooo oor or- ora orc orn oro orr ra- raa rac ran rao rar rca rcc rcn rco rcr rna rnc rnn rno rnr roa roc ron roo ror rra rrc rrn rrr