You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[5-[(4-chlorophenyl)methylsulfanyl]-1,3,4-thiadiazol-2-yl]-1'-ethyl-7-methylspiro[chromeno[2,3-c]pyrrole-1,3'-indole]-2',3,9-trione .
user
C30H21ClN4O4S2
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