You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[[2-(4-aminosulfanylphenoxy)-6-oxo-8-piperazin-1-yl-7-prop-1-ynyl-8,9-dihydropurin-1-yl]methyl]benzonitrile into its molecular formula.
user
C26H26N8O2S
assistant