Let \( a \in \mathbb{R} \) and \( A \) be a matrix of order \( 3 \times 3 \) such that \( \det(A) = -4 \) and
, where \( I \) is the identity matrix of order \( 3 \times 3 \). If \( \det\!\big((a+1)\operatorname{adj}((a-1)A)\big) \) is \( 2^{m}\,3^{n} \), \( m, n \in \{ 0 \), \( 1 \), \( 2 \), \( \ldots \), \( 20 )\} \), then \( m+n \) is equal to: