what is the fuel used by rockets with the smallest number of engines?
Entity Entity Entity
m.021vvd m.01tm_5 m.0g0nz
RP-1 Liquid oxygen Liquid hydrogen
class class literal
spaceflight.rocket_fuel spaceflight.rocket_stage 0^^http://www.w3.org/2001/XMLSchema#int
spaceflight.rocket_fuel spaceflight.rocket_stage type.int
Rocket Fuel Rocket Stage 0
none none argmin
spaceflight.rocket_fuel.rocket_stages spaceflight.rocket_stage.number_of_engines
Rockets Number Of Engines
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :spaceflight.rocket_fuel . 
?x1 :type.object.type :spaceflight.rocket_stage . 
{
SELECT (MIN(?y2) AS ?x2)  WHERE { 
?y0 :type.object.type :spaceflight.rocket_fuel . 
?y1 :type.object.type :spaceflight.rocket_stage . 
?y0 :spaceflight.rocket_fuel.rocket_stages ?y1 . 
?y1 :spaceflight.rocket_stage.number_of_engines ?y2 . 
FILTER ( ?y0 != ?y1 && ?y0 != ?y2 && ?y1 != ?y2  )
}
}
?x0 :spaceflight.rocket_fuel.rocket_stages ?x1 . 
?x1 :spaceflight.rocket_stage.number_of_engines ?x2 . 
FILTER ( ?x0 != ?x1 && ?x0 != ?x2 && ?x1 != ?x2  )
}
}
(ARGMIN spaceflight.rocket_fuel (JOIN spaceflight.rocket_fuel.rocket_stages spaceflight.rocket_stage.number_of_engines))