You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 3-(7-chloro-1-methyl-2-oxo-5-phenyl-3H-1,4-benzodiazepin-3-yl)-1-(2-cyanoethyl)-1-methylthiourea into its molecular formula.
user
C21H20ClN5OS
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