Definition: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
Input: The Pentagon is the headquarters of the United States Department of Defense .
Output:
The Pentagon is the headquarters building of the United States Department of Defense , although as a symbol of the U.S. military , the phrase " The Pentagon " is also often used as a metonym for the Department of Defense and its leadership .