You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-ethyl-4-methyl-N-[(4-phenyl-1,2,4-triazol-3-yl)methyl]thiophene-2-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C17H18N4OS
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