You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-(2-oxo-2-pyrrolidin-1-ylethyl)-2-[[5-[(E)-2-phenylethenyl]-1H-1,2,4-triazol-3-yl]sulfanyl]acetamide into its molecular formula.
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C18H21N5O2S
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