24864
Multivariate analysis showed that sildenafil therapy , functional class and mean pulmonary arterial pressure were independently associated with survival .
 Chemical: sildenafil
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: sildenafil 
Answer:
 Chemical: sildenafil