#P7250. Even Tree Split

    ID: 6107 远端评测题 2000ms 512MiB 尝试: 0 已通过: 0 难度: (无) 上传者: 标签>2022“杭电杯”中国大学生算法设计超级联赛(10)

Even Tree Split

Problem Description

You are given an undirected tree with $n$ nodes. It's guaranteed that $n$ is even.

You are going to delete some of the edges (at least $1$), and have to let each of the remaining connected components have an even number of vertices.

Calculate the number of ways to delete the edges that satisfy such constraints, modulo $998244353$.

Input

The first line contains an integer $T(1 \leq T \leq 30)$ - the number of test cases.

The first line of each test case contains an integer $n(1 \leq n \leq 10^5)$ - the number of vertices on the tree.

The next $n-1$ lines of each test case contain two integers $u,v(1 \leq u,v \leq n)$, representing an edge between $u$ and $v$.

It is guaranteed that the input graph is a tree with even number of vertices.

Output

For each test case, output the number of ways to delete the edges that satisfy such constraints in a single line, modulo $998244353$.

2 2 1 2 4 1 2 2 3 3 4
0 1