About how many decades was it between Ponhea Chan becoming king and the Dutch leaving the trading posts they'd maintained since 1643?
return Ponhea Chan becoming king ;return the  Dutch leaving the trading posts they 'd maintained since 1643 ;return when  was  #1 ;return when  was  #2 ;return difference of #3 and  #4 in  decades
['select', 'select', 'project', 'project', 'arithmetic']