We can compute the {\em diameter} of the tree $T$ by slightly modifying the algorithm we used in previous question. \par \begin {enumerate} \item Remove all leaves of $T$. Let the remaining tree be $T_{1}$. \item Remove all leaves of $T_{1}$. Let the remaining tree be $T_{2}$. \item Repeat the ``remove'' operation as follows: Remove all leaves of $T_{i}$. Let remaining tree be $T_{i+1}$. \item When the remaining tree has only one node or two nodes, stop! Suppose now the remaining tree is $T_{k}$. \item If $T_{k}$ has only one node, that is the center of $T$. The {\em diameter} of $T$ is $2k$. \item If $T_{k}$ has two nodes, either can be the center of $T$. The {\em diameter} of $T$ is $2k+1$. \end {enumerate}