You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 2-[(2R)-2',4-dioxospiro[1,3-dihydroquinazoline-2,5'-azepane]-1'-yl]-N-(1,3-thiazol-2-yl)acetamide ?
user
C18H19N5O3S
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