Given a tree consisting of $$$n$$$ nodes.
Is there a walk that visits all the nodes of the tree at least once and at most twice?
Note that the node you start the walk at is considered visited at the beginning.
A walk is a sequence of nodes $$$v_1, v_2, \dots, v_k$$$ such that for each $$$i$$$ ($$$1 \le i \lt k$$$), $$$v_i$$$ and $$$v_{i + 1}$$$ are connected by an edge.
The first line of the input contains a single integer $$$t$$$ ($$$1 \le t \le 10^5$$$) — the number of testcases.
The first line of each testcase contains a single integer $$$n$$$ ($$$2 \le n \le 2 \cdot 10^5$$$) — the number of nodes in the tree.
Each of the following $$$n - 1$$$ lines of each testcase consists of two space-separated integers $$$u$$$ and $$$v$$$ ($$$1 \le u, v \le n$$$) denoting an edge between nodes $$$u$$$ and $$$v$$$ in the tree.
It is guaranteed that the given edges form a tree.
It is guaranteed that the sum of $$$n$$$ over all the testcases will not exceed $$$2 \cdot 10^5$$$.
For each testcase, print "YES" (without quotes) if there exists a walk that satisfies the conditions, otherwise print "NO" (without quotes).
You can output "YES" and "NO" in any case (for example, strings "yEs", "yes", "Yes" and "YES" will be recognized as a positive response).
321 251 21 33 43 552 11 31 41 5
YES YES NO
Explanation of the first testcase: we can start at node $$$1$$$ then go to node $$$2$$$ and stop there.
Explanation of the second testcase: a valid walk may look like this: $$$5$$$ — $$$3$$$ — $$$4$$$ — $$$3$$$ — $$$1$$$ — $$$2$$$ — $$$1$$$.
Notice that it is not necessary to start at node $$$1$$$.
Nodes $$$1$$$ and $$$3$$$ were visited twice, whereas nodes $$$2$$$, $$$4$$$, and $$$5$$$ were visited once. Thus, each node is visited at least once and at most twice and the walk is valid.
Explanation of the third testcase: it can be shown that there does not exist a walk that satisfies the conditions.
