You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 25-chloro-8-oxa-20lambda6-thia-6,14,21,26,27-pentazatetracyclo[20.3.1.115,19.02,7]heptacosa-1(25),2(7),3,5,15(27),16,18,22(26),23-nonaene 20,20-dioxide into molecular formula.
user
C20H20ClN5O3S
assistant