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 (1S,3S,5R,6R,7R,9R,11S,12R,14S,16R,17R,18R,20R,22S,23R,24R,25R,26R,27R,28R)-25,28-diacetamido-23,24,26,27-tetrahydroxy-5,16-bis(hydroxymethyl)-6,17-disulfooxy-2,4,8,10,13,15,19,21-octaoxapentacyclo[18.2.2.29,12.13,7.114,18]octacosane-11,22-dicarboxylic acid .
user
C28H42N2O28S2
assistant