You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[[(2S)-1-(2,2-dimethylpropanoyl)pyrrolidine-2-carbonyl]amino]-1-methyl-3-propan-2-ylurea The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H28N4O3
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