Surface Area and Volume · Superchallenge problem

Fourteen $1$-cm cubes are glued into a stepped tower standing on a table: a $3$ by $3$ layer of $9$ cubes on the bottom, a $2$ by $2$ layer of $4$ cubes on top of it pushed into one corner, and $1$ cube on top of that, pushed into the same corner. What is the surface area of the tower, including the bottom, in square centimeters?