Vectors in Space · Superchallenge problem

The vectors $\mathbf a, \mathbf b, \mathbf c$ satisfy $\mathbf a \cdot (\mathbf b \times \mathbf c) = 5$. Find the scalar triple product $(\mathbf a \times \mathbf b) \cdot \big( (\mathbf b \times \mathbf c) \times (\mathbf c \times \mathbf a) \big)$.