How many months passed between Edward launching a punitive expedition into North Wales and negotiating a settlement with Llywelyn?
return Edward launching a punitive expedition into North Wales ;return negotiating a settlement with Llywelyn ;return when  was  #1 ;return when  was  #2 ;return difference of #3 and  #4 in  months
['select', 'select', 'project', 'project', 'arithmetic']