题号：NC51116
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 32 M，其他语言64 M
64bit IO Format: %lld
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 32 M，其他语言64 M
64bit IO Format: %lld
题目描述
Give a tree with 
vertices,each edge has a length(positive integer less than 1000).
Define dist(u,v)=The min distance between node
and 
.
Give an integer
,for every pair (u,v) of vertices is called valid if and only if dist(u,v) not exceed .
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
Give an integer
Write a program that will count how many pairs which are valid for a given tree.
输入描述:
The input contains several test cases. The first line of each test case contains two integersThe following
lines each contains three integers
, which means there is an edge between node
. The last test case is followed by two zeros.
输出描述:
For each test case output the answer on a single line.