79841
Occasionally , letters " a " and " b " are applied to luminosity classes other than supergiants ; for example , a giant star slightly more luminous than typical may be given a luminosity class of IIIb .
 IIIb
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 IIIb