20404
The first GaS nanosheet - based photodetectors are demonstrated on both mechanically rigid and flexible substrates .
 Chemical: GaS
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: GaS 
Answer:
 Chemical: GaS