You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[3-(4-chlorophenyl)-2,2-dioxo-2lambda6-thia-1-azaspiro[4.4]non-3-en-4-yl]methyl]-N-(2-fluoroethyl)propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H24ClFN2O3S
assistant