Totalling stock level gives a circular error

Hi. I've hit a brick wall in my thinking and sure that this is something simple but cannot get around this wall!

I've attached a very simplified example of what I'm trying to achieve:

A2 is a starting value. B2 is a calculated Total (realistically from formulas referencing other worksheets showing sales / orders etc)

E2 is where I enter the result from a manual stock check, but I'd also like the Total Litres in B2 to update for this manual stock check. I.e. what I was thinking was to change the formula in B2 to =A$2+50+F2 which, of course, is giving a circular error.

Can someone please help with how I can achieve this?

Worked perfectly, Mehmetcik. Thank you very much