题目描述
Snuke's mother gave Snuke an undirected graph consisting of N vertices numbered 0 to N-1 and M edges. This graph was connected and contained no parallel edges or self-loops.
One day, Snuke broke this graph. Fortunately, he remembered Q clues about the graph. The $i-th clue (0 \leq i \leq Q-1)$ is represented as integers A_i,B_i,C_i and means the following:
- If C_i=0: there was exactly one simple path (a path that never visits the same vertex twice) from Vertex A_i to B_i.
- If C_i=1: there were two or more simple paths from Vertex A_i to B_i.
Snuke is not sure if his memory is correct, and worried whether there is a graph that matches these Q clues. Determine if there exists a graph that matches Snuke's memory.
Constraints
- $2 \leq N \leq 10^5$
- $N-1 \leq M \leq N \times (N-1)/2$
- $1 \leq Q \leq 10^5$
- $0 \leq A_i,B_i \leq N-1$
- $A_i \neq B_i$
- $0 \leq C_i \leq 1$
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
N M Q
A_0 B_0 C_0
A_1 B_1 C_1
$\vdots$
A_{Q-1} B_{Q-1} C_{Q-1}
Output
If there exists a graph that matches Snuke's memory, print Yes; otherwise, print No.
Examples
Input
5 5 3
0 1 0
1 2 1
2 3 0
Output
Yes
Input
4 4 3
0 1 0
1 2 1
2 3 0
Output
No
Input
10 9 9
7 6 0
4 5 1
9 7 0
2 9 0
2 3 0
4 1 0
8 0 0
9 1 0
3 0 0
Output
No
输入格式
见题面
输出格式
见题面