1646
In addition , delivery delays for the first two of as many as 28 Boeing 747 - 400s that the carrier has ordered have raised costs because personnel had been hired to man the planes .
 first, two, as many as 28, Boeing, 747 - 400s
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: date, organization, person, geographical social political, national religious political, facility, cardinal, location, work of art, law, event, product, ordinal, percent, time, quantity, money, language 
Text: {0} 
Answer:
 first, two, as many as 28, Boeing, 747 - 400s