You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-(ethoxycarbonylamino)-3-[[2-hydroxy-4-[2-(3,4,5,6-tetrahydro-2H-azepin-7-ylamino)ethoxy]benzoyl]amino]propanoic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H30N4O7
assistant