1504
Atypical femoral fractures ( AFF ) associated with long - term bisphosphonates ( LTB ) are a growing concern .
 Chemical: bisphosphonates
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: bisphosphonates