You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[6-[2-[[4-amino-5-[(4-ethylpiperazin-1-yl)methyl]pyridin-2-yl]amino]-5-fluoropyrimidin-4-yl]-4-fluoro-2-methylbenzimidazol-1-yl]propanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H31F2N9O2
assistant