The "F" is for TDC front cylinder makes it easy to get bolts out of cam sprocket.
Doesn't need to be at "F" as long as you can get the cam out. Take the timing chain tensioner out first. Sometimes the is enough slack you can lift the end of the cam away from the sprocket and work the chain off the cam sprocket without removing the bolts.
Oh ok cool thanks I was wondering how I was going to get it out thought it had to be on "F"