You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[1-(2-ethyl-1,3-thiazol-4-yl)ethyl]-3-[(3-methyl-1,2-oxazol-5-yl)methyl]urea is the IUPAC name of a molecule. Please give its molecular formula.
user
C13H18N4O2S
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