You are given a tree consisting of $n$ nodes.
The diameter of a tree is the maximum distance between two nodes. Your task is to determine the diameter of the tree.
The first input line contains an integer $n$ : the number of nodes. The nodes are numbered $1,2,\ldots,n$ .
Then there are $n-1$ lines describing the edges. Each line contains two integers $a$ and $b$ : there is an edge between nodes $a$ and $b$ .
Print one integer: the diameter of the tree.
5 1 2 1 3 3 4 3 5\n · \n · \n · \n · \n
3\n
The diameter corresponds to the path $2 \rightarrow 1 \rightarrow 3 \rightarrow 5$ .