Alzheimers' Eye Test

I don't know why it's called "Alzheimer's Eye Test", but it's as stated in the email I just received. I think I've received this before and yet failed the test again! You might have come across this. If you haven't, then take the test. (Please don't scroll down for the answer.)

Count every ' F' in the following text:


FINISHED FILES ARE THE RE
SULT OF YEARS OF SCIENTI
FIC STUDY COMBINED WITH
THE EXPERIENCE OF YEARS...



HOW MANY ? READ IT AGAIN !
(Please don't scroll down until you have decided on your answer)









The answer is A-B where:
A is 7+4+8+5+8+8+3+8
B is 7+4+5+7+2+4+8+3+5



The reasoning behind is further down.

















Incredible or what? Go back and look again!! Anyone who counts all the 'F's' on the first go is a genius. Three is normal, four is quite rare.

(If you got it right on the first attempt, please let me know. You're a genius!!)

The brain cannot process 'of'.