Problem 4842. -- Poj1741 Tree

## 4842: Poj1741 Tree

Time Limit: 1 Sec  Memory Limit: 30 MB
Submit: 18  Solved: 13
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## Description

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.

## Input

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.

## Output

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

## Sample Input

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

## Sample Output

8

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