- Time limit: 1.00 s
- Memory limit: 512 MB
Input
The first input line contains two integers $n$ and $k$: the number of nodes and the path length. The nodes are numbered $1,2,\ldots,n$.
Then there are $n-1$ lines describing the edges. Each line contains two integers $a$ and $b$: there is an edge between nodes $a$ and $b$.
Output
Print one integer: the number of paths.
Constraints
- $1 \le k \le n \le 2 \cdot 10^5$
- $1 \le a,b \le n$
Input:
5 2
1 2
2 3
3 4
3 5
Output:
4