题号：NC252124
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 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 256 M，其他语言512 M
64bit IO Format: %lld
题目描述
Given a tree with 
nodes numbered from 
to .
Alice wants to know the number of connected components with a size of three in the tree.
Alice wants to know the number of connected components with a size of three in the tree.
输入描述:
The first line contain a single integer, denoting the number of nodes in the tree.
In the nextlines, each line contain two integers
and
, indicating that there is an edge between node
.
输出描述:
Output an integer in a single line, indicating the number of connected components with a size of three in the tree.