120617
This is a list of confirmed tornadoes produced by the Mid-May 2008 tornado outbreak sequence , which spawned a total of at least 146 tornado es confirmed across the southern United States from May 7 to May 15 , 2008 .
 United States
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 United States