9148
The Maybach engines had been a never-ending source of trouble on the R. II , R. III , and R. IV , and during 1916 , the engines of the R. III , R. IV , R. V , and R. VI were replaced with Benz Bz . IV engines either at the factory or in the field , while the R. II received the more powerful Mercedes D. IVa .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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