You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(2Z,5S)-3-(4-hydroxyphenyl)-2-[(Z)-(2-hydroxyphenyl)methylidenehydrazinylidene]-4-oxo-1,3-thiazolidin-5-yl]acetic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H15N3O5S
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