You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as 1-[1-[(3,4-dichlorophenyl)methyl]pyrazol-3-yl]-3-[(4-fluorophenyl)methyl]thiourea using the IUPAC nomenclature.
user
C18H15Cl2FN4S
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