You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (2S)-1-[4-[(4-ethylphenyl)methyl]-7-[(2S)-2-hydroxypropyl]-1,4,7-triazonan-1-yl]propan-2-ol ?
user
C21H37N3O2
assistant