For each positive integer n , the set of integers is known as the n . Within the residue system modulo , let A be the

For each positive integer n , the set of integers \(\{0,1,\ldots,n-1\}\)  is known as the \(\textit{residue system modulo}\)  n . Within the residue system modulo \(2^4\)  , let  A be the sum of all invertible integers modulo \(2^4\)   and  let B be the sum all of non-invertible integers modulo \(2^4\) . What is  A-B?