You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,6R,7R)-4-methyl-8-oxo-7-(phenylmethoxycarbonylamino)-5-thia-1-azatricyclo[4.2.0.02,4]octane-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H16N2O5S
assistant