Question: The KVLY-TV mast is the fourth tallest structure in the world behind the megatall skyscraper that is how many stories in height?
Sentence (from "KVLY-TV mast"): It remains the fourth-tallest structure in the world (since the construction of the Tokyo Skytree and the Shanghai Tower), the tallest structure in the western hemisphere, and the tallest radio mast in the world.
Relevant evidence: Yes