30584
Commercially viable natural deposits of graphite occur in many parts of the world , but the most important sources economically are in China , India , Brazil and North Korea .
 China, India, Brazil, North Korea
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 China, India, Brazil, North Korea