5. In a $2008 \times 2008 \times 2008$ cube, if a line is drawn such that it passes through the centers of 2008 unit cubes, then the number of such lines that can be drawn is $\qquad$.
5. 12108244 Explanation: Such straight lines can be divided into three categories. There are $2008 \times 2008 \times 3+2008 \times 2 \times 3+4=12108244$ in total.