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A message from the West this week from U.S. President Bill Clinton congratulated Ukraine on the anniversary , promising to support market reforms and praising Ukraine as a " stabilising factor " in a united Europe .
 U.S., Ukraine, Bill Clinton, Ukraine, Europe
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, else, organization, person 
Text: {0} 
Answer:
 U.S., Ukraine, Bill Clinton, Ukraine, Europe