In mathematics, and more specifically in graph theory, a tree is an undirected graph in which any two nodes are connected by exactly one path. In other words, any connected graph without simple cycles is a tree.
You find a partial tree on the way home. This tree has $n$ nodes but lacks of $n-1$ edges. You want to complete this tree by adding $n-1$ edges. There must be exactly one path between any two nodes after adding. As you know, there are $n^{n-2}$ ways to complete this tree, and you want to make the completed tree as cool as possible. The coolness of a tree is the sum of coolness of its nodes. The coolness of a node is $f(d)$, where $f$ is a predefined function and $d$ is the degree of this node. What's the maximum coolness of the completed tree?