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 N-[4-(4-butylphenyl)-1,3-thiazol-2-yl]-2-[2-(2-oxoimidazolidin-1-yl)-1,3-thiazol-4-yl]acetamide .
user
C21H23N5O2S2
assistant