You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[[(5Z)-5-[(2-hydroxy-3-methoxyphenyl)methylidene]-4-oxo-1,3-thiazolidin-2-ylidene]amino]-4,5-dimethoxybenzoic acid .
user
C20H18N2O7S
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