4721
Over several years beginning in 1939 , a total of 447 Finches were built , nearly all ( 431 ) of them for use as elementary trainers in the British Commonwealth Air Training Plan ( BCATP ) during the Second World War .
 None
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:  
Answer:
 None