Eye Exam

Count the number of F's in the following text:

FINISHED FILES ARE THE
RESULT OF YEARS OF SCIENTIFIC
STUDY COMBINED WITH THE
EXPERIENCE OF YEARS

How many? Tell me your first answer.

Three?

Count again.

FINISHED FILES ARE THE
RESULT OF YEARS OF SCIENTIFIC
STUDY COMBINED WITH THE
EXPERIENCE OF YEARS

There are six F in the text.

Most of us will count only three F by ignoring those in "OF" before we read the answer. This is because our brain did not process the word "OF". Those who count six F at the first time are genius. Don't cheat if you already found this somewhere else.