The Table Below Represents a Portion of a Computer's Main

The table below represents a portion of a computer's main memory containing a binary tree.Each node consists of three cells,the first being data,the second being a pointer to the node's left child,and the third being a pointer to the node's right child.If the null pointer is represented by 00 and the tree's root pointer contains 53,how many terminal nodes are in the tree?
$\begin{array} { c c } \text { Address } & \text { Contents } \\50 & \mathrm { AA } \\51 & 00 \\52 & 00 \\53 & \mathrm { BB } \\54 & 00 \\55 & 56 \\56 & \mathrm { CC } \\57 & 00 \\58 & 00\end{array}$