returning positive number regardless

Hi im trying to work out the best way to do following.
i have a list of numbers in column A and B and in column C is = B - A.
But what i want is for Column C to always = positive number regardless even if say A = 10 and B = 8 the true answer is -2 but i would like the reading of 2.
Is there a way to say B - A and if = - make it -( ) ? (otherwords +)

thanks heaps troy