How many months after Marienburg, Dirschau and Eylau were taken was Kneiphof also taken?
return Marienburg ,  Dirschau and  Eylau were taken ;return Kneiphof was  taken ;return when  was  #1 ;return when  was  #2 ;return difference of #4 and  #3 in  months
['select', 'select', 'project', 'project', 'arithmetic']