P8244 [CF2018C] Tree Pruning
普及+
题目描述

You are given a tree with $n$ nodes, rooted at node $1$. In this problem, a leaf is a non-root node with degree $1$.

In one operation, you can remove a leaf and the edge adjacent to it (possibly, new leaves appear). What is the minimum number of operations that you have to perform to get a tree, also rooted at node $1$, where all the leaves are at the same distance from the root?

Input

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.

The first line of each test case contains a single integer $n$ ($3 \leq n \leq 5 \cdot 10^5$) — the number of nodes.

Each of the next $n-1$ lines contains two integers $u$, $v$ ($1 \leq u, v \leq n$, $u \neq v$), describing an edge that connects $u$ and $v$. It is guaranteed that the given edges form a tree.

It is guaranteed that the sum of $n$ over all test cases does not exceed $5 \cdot 10^5$.

Output

For each test case, output a single integer: the minimum number of operations needed to achieve your goal.

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
3 7 1 2 1 3 2 4 2 5 4 6 4 7 7 1 2 1 3 1 4 2 5 3 6 5 7 15 12 9 1 6 6 14 9 11 8 7 3 5 13 5 6 10 13 15 13 6 14 12 7 2 8 1 1 4
样例输出
2 2 5
提示

In the first two examples, the tree is as follows:

In the first example, by removing edges $(1, 3)$ and $(2, 5)$, the resulting tree has all leaves (nodes $6$ and $7$) at the same distance from the root (node $1$), which is $3$. The answer is $2$, as it is the minimum number of edges that need to be removed to achieve the goal.

In the second example, removing edges $(1, 4)$ and $(5, 7)$ results in a tree where all leaves (nodes $4$ and $5$) are at the same distance from the root (node $1$), which is $2$.