245035
It was a basic and conventional design : a parasol wing monoplane with tailskid undercarriage and seating for two in tandem open cockpit s. The type proved extremely popular , and the production run would eventually extend to over 500 machines , with roughly half of these purchased by the Regia Aeronautica as trainer s and liaison aircraft .
 Regia Aeronautica
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Regia Aeronautica