Task: Question Generation
Input (English): #1 return days 
#2 return mean  humidity of  #1 
#3 return mean  visibility of  #1 
#4 return #1 where  #2 is  higher than 50 
#5 return #1 where  #3 is  higher than 8 
#6 return #1 of  both #4 and #5
Output (English): How many days had both mean humidity above 50 and mean visibility above 8?