instruction:
In this task, you will be given a set of steps that are required to answer a specific question. Your job is to generate that question. Each given step refers to either an entity (known or unknown), a propery of an entity or a query operation (count, group, union, etc.) Knowing those operations and how they appear in the input may help you generate more accurate questions.
 Select: A select step is used to return a set of objects. There are no references to previous steps in a select step. template: Return [attributes]
 Filter: A filter step is used to return results from a previous step to which a certain condition applies. template: Return [#step] [condition]
 Project: A project step should return certain attributes of the results of a previous step. template: Return [attributes] of [#step]
 Aggregate: An aggregate step returns an aggregator function applied on a step's result. template: Return the [aggregator] of [#step].
 Group: A group step is an aggregator applied on attributes. template: Return the [aggregator] of [#step] for each [attribute]
 Superlative: A superlative step is used to return the result with a highest/lowest attribute among other results. template: Return [#step1] [where] [#step2] [is] [highest / lowest]
 Comparative: A comparative step is used when we need to compare an attribute with a number to filter results. template: Return [#step1] [where] [#step2] [comparator] [number] 
 Union: A union step is used to return results of two steps together. template: Return [#step1] [or / ,] [#step2]
 Intersection: An intersection step returns the result that two steps have in common. template: Return [attribute] of both [#step1] and [#step2]
 Discard: A discard step returns result of a step and excludes result of another step from it. template: Return [#step1] besides [#step2]
 Sort: A sort returns result of another step in a specific order. template: Return [#step1] [ordered / sorted by] [#step2]
 Is true: An is true step checks a condition on another result and returns a true or false. template: Return [is / if] [condition]
 Arithmetic: An arithmatic step operates an arithmatic operation on one or more steps. template: Return the [arithmetic op.] of [#step1] [and] [#step2].
question:
#1 return flights 
#2 return #1 between boston and  philadelphia 
#3 return the most expensive #2
answer:
the most expensive flight between boston and philadelphia 


question:
#1 return right image 
#2 return gorilla in  #1 
#3 return #2 that is an adult 
#4 return #3 that is male 
#5 return arms of #4 
#6 return ground in  #1 
#7 return #5 that are extended down to  #6 
#8 return body of #4 
#9 return #7 that are in  front of #8 
#10 return #2 that has #9 
#11 return number of  #10 
#12 return if  #11 is equal to  one 
#13 return number of  #2 
#14 return if  #13 is equal to  one 
#15 return if  both  #14 and #12 are true
answer:
If the right image contains one gorilla, an adult male with its arms extended down to the ground in front of its body.


question:
#1 return product ids 
#2 return documents of  #1 
#3 return document type codes of  #2 
#4 return #2 where  #3 is  BK 
#5 return number of #4 for each #1
answer:

How many documents are with document type code BK for each product id?