Task: Question Generation
Input (English): #1 return the  French occupied towns such as Frankfurt ,  Hanau and  Darmstadt 
#2 return the  Reichswehr did control all of the   northern Ruhr area 
#3 return when  was  #1 
#4 return when  was  #2 
#5 return difference of #3 and  #4 in  days
Output (English): How many days after the French occupied towns such as Frankfurt, Hanau and Darmstadt did the Reichswehr control all of the northern Ruhr area?