题目描述
Copil Copac is given a list of $n-1$ edges describing a tree of $n$ vertices. He decides to draw it using the following algorithm:
- Step $0$: Draws the first vertex (vertex $1$). Go to step $1$.
- Step $1$: For every edge in the input, in order: if the edge connects an already drawn vertex $u$ to an undrawn vertex $v$, he will draw the undrawn vertex $v$ and the edge. After checking every edge, go to step $2$.
- Step $2$: If all the vertices are drawn, terminate the algorithm. Else, go to step $1$.
The number of readings is defined as the number of times Copil Copac performs step $1$.
Find the number of readings needed by Copil Copac to draw the tree.
Input
Each test contains multiple test cases. The first line of input contains a single integer $t$ ($1 \leq t \leq 10^4$) — the number of test cases. The description of test cases follows.
The first line of each test case contains a single integer $n$ ($2 \le n \le 2 \cdot 10^5$) — the number of vertices of the tree.
The following $n - 1$ lines of each test case contain two integers $u_i$ and $v_i$ ($1 \le u_i, v_i \le n$, $u_i \neq v_i$) — indicating that $(u_i,v_i)$ is the $i$-th edge in the list. 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 $2 \cdot 10^5$.
Output
For each test case, output the number of readings Copil Copac needs to draw the tree.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first test case:
After the first reading, the tree will look like this:
After the second reading:
Therefore, Copil Copac needs $2$ readings to draw the tree.