What is the molecular formula of aspirin?

What is the molecular formula of aspirin?
C9H8O4...
Tried to cheat in my first year chemistry at medchool by taking commercial asprin and hand it in instead of making my own...
When the Prof. took my indication and put it into the atom mass spectrometer, he discovered me...thought it was awfully funny, i had to spend the subsequent week making asprin every day...
C9H8O4
Acetylsalicylic sharp, C9 H8 O4
2-acetoxybenzoic acid
CHCHCHCHCOCCOOH
.......................CO
.......................CH3
C9H8O4
c9h8o4
If you know chemistry, it is acetyl salicylic tart.