You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-(6-fluoro-1H-indol-3-yl)-N-[1-[[(2S)-oxolan-2-yl]methyl]pyrazol-4-yl]acetamide into molecular formula.
user
C18H19FN4O2
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