You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-ethoxyiminoacetyl]amino]-3-[(6-chloropyrrolo[1,2-a]pyrazin-2-ium-2-yl)methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid .
user
C22H21ClN7O5S2+
assistant