问题 A: Tree!

Give a tree with n vertices,each edge has a length(positive integer less than 1001). 
Define dist(u,v)=The min distance between node u and v. 
Give an integer k,for every pair (u,v) of vertices is called valid if and only if dist(u,v) not exceed k. 
Write a program that will count how many pairs which are valid for a given tree. 

The input contains several test cases. The first line of each test case contains two integers n, k. $(n ≤ 10000) $The following n-1 lines each contains three integers u,v,l, which means there is an edge between node u and v of length l.
The last test case is followed by two zeros.

For each test case output the answer on a single line.

5 4
1 2 3
1 3 1
1 4 2
3 5 1
0 0

8