Height of the Tree

Difficulty: 1200 4000 ms 128 MB

bfs trees

A tree is rooted at node 1. Print its height — the number of edges on the longest root-to-leaf path.

Input: the first line has N; each of the next N−1 lines has an edge u v.

Output: the height (0 for a single node).

Constraints:

• 1 ≤ N ≤ 10⁵

Sample Tests

5
1 2
1 3
3 4
4 5

3

1

0

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