338041
Background On 26 February 1941 the USAAC placed a contract with Bell allowing for the purchase of two XP-39Es ( 41-19501 and 41-19502 ) which were envisaged to be a major improvement on the P-39D series .
 USAAC
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 USAAC