Problem Statement
You are given a simple directed acyclic graph $G$ with $N$ vertices numbered $1$ to $N$. $G$ has $M$ edges, and the $i$-th edge is directed from vertex $x_i$ to vertex $y_i$.
A permutation $P=(P_1,P_2,\ldots,P_N)$ of $(1,2,\ldots,N)$ that satisfies the following condition is called a special permutation:
$P_{x_i} \lt P_{y_i}$for all$i=1,2,\cdots,M$.
You are given a special permutation $P$. Takahashi and Aoki will play a game using it. Takahashi knows the value of each term of $P$, but Aoki only knows that $P$ is a special permutation. Both of them know $G$. Takahashi selects some terms of $P$ and tells Aoki their positions and values. Find the minimum number of terms that Takahashi needs to tell Aoki so that Aoki can determine the values of all terms of $P$.
Solve $T$ test cases per input.
Constraints
$1 \leq T \leq 10^4$$1 \leq N \leq 2 \times 10^5$$0 \leq M \leq 2 \times 10^5$$1 \leq x_i,y_i \leq N$- The given graph
$G$is a simple directed acyclic graph. $1 \leq P_i \leq N$$P_1,P_2,\ldots,P_N$are pairwise distinct.$P_{x_i} \lt P_{y_i}$- The sum of
$N$over all test cases is at most$2 \times 10^5$. - The sum of
$M$over all test cases is at most$2 \times 10^5$. - All input values are integers.
Input
The input is given from Standard Input in the following format:
T
case_1
case_2
\vdots
case_T
Each case is given in the following format:
N M
x_1 y_1
x_2 y_2
\vdots
x_M y_M
P_1 P_2 \ldots P_N
Output
Output $T$ lines in total. The $t$-th line should contain the answer for the $t$-th test case.
样例
3
5 4
3 4
4 1
3 1
5 2
5 4 1 2 3
4 0
4 2 1 3
10 15
6 2
8 5
4 9
7 10
3 7
5 6
8 9
3 5
5 2
8 2
3 9
5 9
10 2
3 2
7 4
8 9 2 6 4 5 3 1 10 7
2
3
6
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