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 line contains an integer n(1≤n≤2⋅105) — the number of nodes. The nodes are numbered 1, 2, ..., n.
Then there are n−1 lines describing the edges. Each line contains two integers a and b(1≤a,b≤n) — there is an edge between nodes a and b.
Print one integer — the diameter of the tree.