问题 A: Tree!
内存限制:128 MB
时间限制:1.000 S
评测方式:文本比较
命题人:
提交:15
解决:2
题目描述
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.
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.
输入
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.
The last test case is followed by two zeros.
输出
For each test case output the answer on a single line.
样例输入 复制
5 4
1 2 3
1 3 1
1 4 2
3 5 1
0 0
样例输出 复制
8