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Throughout the late 1950 s and into the 1960 s , the United States and the Soviet Union had been developing missile systems with the ability to shoot down incoming ICBM warheads .
 location: United States; location: Soviet Union
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: United States, Soviet Union 
Answer:
 location: United States; location: Soviet Union