question: About how many months did the Albanian refugees stay in Montenegro before they were forced to return to Kosovo Vilayet?
#1 return the  Albanian refugees stay in  Montenegro 
#2 return the  Albanian refugees were forced to return to  Kosovo Vilayet 
#3 return months of #1 
#4 return month of #2 
#5 return the  lowest of #3 
#6 return the  difference of #4 and  #5