318581
However , the Forssman did not meet all the criteria of the " R " designation — for example , its engines were not serviceable in flight — and the " R " designation only came into use after the Forssman was built .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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