And here it is - "Beauty"!
"Deviation from Ideal Beauty" sounds a bit long, isn't it? Let's call it just "Beauty" and understand it as geometric deviation from Ideal Beauty. For instance, suppose we get "Deviation" equal to 0,121. It means that our beauty differs from ideal beauty by 0,121. Now lose this zero and the value of "121" will be the Beauty.

Beauty that equals to zero is Ideal Beauty. The closer the Beauty value to zero is, the more beautiful the face is. This face has small deviation from perfection.