You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-chloro-N-[[3-[(2-pyrazol-1-ylacetyl)amino]phenyl]methyl]-1-benzofuran-2-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H17ClN4O3
assistant