1213
In addition , the extended connectivity fingerprints ( ECFP _ 4 ) for all the molecules were calculated and structure - activity relationship of Aurora kinase inhibitors was summarized , which may be helpful to find the important structural features of inhibitors relating to the selectivity to Aurora kinases .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None