#agc038d. [agc038_d]Unique Path
[agc038_d]Unique Path
Problem Statement
Snuke's mother gave Snuke an undirected graph consisting of vertices numbered to and edges. This graph was connected and contained no parallel edges or self-loops.
One day, Snuke broke this graph. Fortunately, he remembered clues about the graph. The -th clue () is represented as integers and means the following:
- If : there was exactly one simple path (a path that never visits the same vertex twice) from Vertex to .
- If : there were two or more simple paths from Vertex to .
Snuke is not sure if his memory is correct, and worried whether there is a graph that matches these clues. Determine if there exists a graph that matches Snuke's memory.
Constraints
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
Output
If there exists a graph that matches Snuke's memory, print Yes
; otherwise, print No
.
Sample Input 1
5 5 3
0 1 0
1 2 1
2 3 0
Sample Output 1
Yes
For example, consider a graph with edges . This graph matches the clues.
Sample Input 2
4 4 3
0 1 0
1 2 1
2 3 0
Sample Output 2
No
Sample Input 3
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
Sample Output 3
No