You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-[3-[[C-(2-azaspiro[5.6]dodecan-2-yl)-N-methylcarbonimidoyl]amino]propyl]cyclobutanecarboxamide into molecular formula.
user
C21H38N4O
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