You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-[[3-(2-hydroxyethyl)-4-[(6-methylpyridin-2-yl)methyl]piperazin-1-yl]methyl]-2-methoxyphenol by IUPAC nomenclature, provide its molecular formula.
user
C21H29N3O3
assistant