You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(5-tert-butyl-1,2,4-oxadiazol-3-yl)methyl]-1-ethyl-3-[2-hydroxy-2-(3-propan-2-yloxyphenyl)ethyl]guanidine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H33N5O3
assistant