题目描述
You are given a weighted undirected graph on $n$ vertices along with $q$ triples $(u, v, l)$, where in each triple $u$ and $v$ are vertices and $l$ is a positive integer. An edge $e$ is called useful if there is at least one triple $(u, v, l)$ and a path (not necessarily simple) with the following properties:
- $u$ and $v$ are the endpoints of this path,
- $e$ is one of the edges of this path,
- the sum of weights of all edges on this path doesn't exceed $l$.
Please print the number of useful edges in this graph.
Input
The first line contains two integers $n$ and $m$ ($2\leq n\leq 600$, $0\leq m\leq \frac{n(n-1)}2$).
Each of the following $m$ lines contains three integers $u$, $v$ and $w$ ($1\leq u, v\leq n$, $u\neq v$, $1\leq w\leq 10^9$), denoting an edge connecting vertices $u$ and $v$ and having a weight $w$.
The following line contains the only integer $q$ ($1\leq q\leq \frac{n(n-1)}2$) denoting the number of triples.
Each of the following $q$ lines contains three integers $u$, $v$ and $l$ ($1\leq u, v\leq n$, $u\neq v$, $1\leq l\leq 10^9$) denoting a triple $(u, v, l)$.
It's guaranteed that:
- the graph doesn't contain loops or multiple edges;
- all pairs $(u, v)$ in the triples are also different.
Output
Print a single integer denoting the number of useful edges in the graph.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first example each edge is useful, except the one of weight $5$.
In the second example only edge between $1$ and $2$ is useful, because it belongs to the path $1-2$, and $10 \leq 11$. The edge between $3$ and $4$, on the other hand, is not useful.
In the third example both edges are useful, for there is a path $1-2-3-2$ of length exactly $5$. Please note that the path may pass through a vertex more than once.