a-a a-c a-t aaa aac aad aao aat ac- aca acc acd aco act ad- ada adc add ado adt aoa aoc aod aoo aot at- ata atc atd ato att c-- caa cac cad cao cat cca ccc ccd cco cct cda cdc cdd cdo cdt co- coa coc cod coo cot cta ctc ctd cto ctt daa dac dad dao dat dca dcc dcd dco dct dda ddc ddd ddo ddt doa doc dod doo dot dta dtc dtd dto dtt oaa oac oad oao oat oc- oca occ ocd oco oct oda odc odd odo odt oo- ooa ooc ood ooo oot ot- ota otc otd oto ott taa tac tad tao tat tca tcc tcd tco tct tda tdc tdd tdo tdt to- toa toc tod too tot tta ttc ttd tto ttt