49110
In May 2019 , former 2020 U.S. presidential campaign police districts chose Philadelphia to be his Frankford headquarters .
 U.S., Philadelphia, Frankford
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 U.S., Philadelphia, Frankford