You are given an undirected graph $G$ consisting of $n$ nodes and $m$ edges, each edge is either marked or unmarked.
Your job is to find out if it's possible to find *any* Vertex Cover of the graph, such that the marked edges can have only one of their endpoints included in the set (but not both).
A Vertex Cover is a subset of the nodes such that each edge in the graph has at least one of its endpoints in this set.
The first line of input contains a single integer $T$ ($1 <= T <= 40$), the number of test cases.
The first line of each test case contains two space-separated integers $n$ and $m$ ($1 <= n <= 10^5$) ($0 <= m <= 10^5$), the number of nodes and edges in the graph, respectively.
Each of the following $m$ lines contains three space-separated integers $u_i$, $v_i$ and $w_i$ ($1 <= u_i, v_i <= n$, $u_i eq.not v_i$) ($0 <= w_i <= 1$), representing that the $i^(t h)$ edge connects the nodes $u_i$ and $v_i$, and the edge is marked if $w_i$ is equal to $1$, otherwise it's unmarked.
For each test case, output a single line with *YES* if it's possible to find such a Vertex Cover, otherwise output *NO*.
## Input
The first line of input contains a single integer $T$ ($1 <= T <= 40$), the number of test cases.The first line of each test case contains two space-separated integers $n$ and $m$ ($1 <= n <= 10^5$) ($0 <= m <= 10^5$), the number of nodes and edges in the graph, respectively.Each of the following $m$ lines contains three space-separated integers $u_i$, $v_i$ and $w_i$ ($1 <= u_i, v_i <= n$, $u_i eq.not v_i$) ($0 <= w_i <= 1$), representing that the $i^(t h)$ edge connects the nodes $u_i$ and $v_i$, and the edge is marked if $w_i$ is equal to $1$, otherwise it's unmarked.
## Output
For each test case, output a single line with *YES* if it's possible to find such a Vertex Cover, otherwise output *NO*.
[samples]
**Definitions**
Let $ T \in \mathbb{Z} $ be the number of test cases.
For each test case, let $ G = (V, E) $ be an undirected graph with:
- $ V = \{1, 2, \dots, n\} $, the set of nodes,
- $ E = E_m \cup E_u $, the set of edges, partitioned into:
- $ E_m $: marked edges ($ w_i = 1 $),
- $ E_u $: unmarked edges ($ w_i = 0 $).
**Constraints**
1. $ 1 \le T \le 40 $
2. For each test case:
- $ 1 \le n \le 10^5 $, $ 0 \le m \le 10^5 $
- Each edge $ e_i = (u_i, v_i, w_i) $ satisfies $ u_i \ne v_i $, $ w_i \in \{0,1\} $
**Objective**
Determine whether there exists a vertex cover $ C \subseteq V $ such that:
- For every edge $ (u,v) \in E $, $ u \in C $ or $ v \in C $ (standard vertex cover condition),
- For every marked edge $ (u,v) \in E_m $, exactly one of $ u $ or $ v $ is in $ C $ (i.e., $ | \{u,v\} \cap C | = 1 $).