4220
He is widely credited with having a serious influence on the work of Roy Lichtenstein , who was a student of his during the forties .
 person: Roy Lichtenstein
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Roy Lichtenstein