You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methanol;N-[3-methoxy-1-[[2-[[4-methyl-1-(2-methyloxiran-2-yl)-1-oxopentan-2-yl]amino]-2-oxoethyl]amino]-1-oxopropan-2-yl]-5-(nitrosomethyl)-1,2-oxazole-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H33N5O9
assistant