How many years passed between the halfhearted reconquest attemp and the fully-fledged reconquest campaign on Navarre?
return the  halfhearted reconquest  attemp ;return the  fully-fledged reconquest  campaign on Navarre ;return year of #1 ;return year of #2 ;return difference of #4 and  #3
['select', 'select', 'project', 'project', 'arithmetic']