24699
Thus , the reaction of the H atom photofragment following H2O photodissociation with CO can be a possible route to form HCO ice .
 Chemical: H; Chemical: H2O; Chemical: CO; Chemical: HCO
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: H, H2O, CO, HCO 
Answer:
 Chemical: H; Chemical: H2O; Chemical: CO; Chemical: HCO