17804
An X - ray crystal structure of optimized compound 9b bound in the active site of FVIIa showed that the bicyclic scaffold provides 5 hydrogen bonding interactions in addition to projecting groups for interactions within the S1 , S2 and S3 pockets .
 Chemical: hydrogen
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: hydrogen