An unrootedRooted binary tree ''T'' may be transformed into a full rootedUnroot [[binary tree]] (that is, a rootedunrooted tree in which each non-leaf node has exactly two children) by choosing a ''rootunroot edge'' ''e'' of ''T'', placing a new rootunroot node in the middle of ''e'', and directing every edge of the resulting subdivided tree away from the rootunroot node. Conversely, any full rootedunrooted binary tree may be transformed into an unrootedrooted binary tree by removing the rootunroot node, replacing the path between its two children by a single undirecteddirected edge, and suppressing the orientation of the remaining edges in the graph. For this reason, there are exactly 2''n'' −3 times as many full rootedunrooted binary trees with ''n'' leaves as there are unrootedrooted binary trees with ''n'' leaves.<ref name="f84"/>
