The solution to the number of spanning trees of the graph below is given by $3 \times 2 \times 3 = 18$. I'm not sure how to get this. Please assist. Thanks!
Notes: Just in case anyone was wondering, I drew the graph using the tool on http://illuminations.nctm.org/Activity.aspx?id=3550 and got the image by using the snipping tool on Windows.