Problem Statement
In this problem, we simply call a tree with $N$ vertices numbered $1,2,\ldots,N$ and unnumbered edges an $N$-vertex tree.
When an $N$-vertex tree $T$ and a permutation $Q=(Q_1,Q_2,\ldots,Q_N)$ of $(1,2,\ldots,N)$ satisfy the following condition, the permutation $Q$ is called a good permutation of tree $T$:
There are
$N$points$1,2,\ldots,N$arranged counterclockwise at equal intervals on a circle in this order. For each edge$\lbrace u,v\rbrace$of tree$T$, draw a line segment connecting the two points$Q_u,Q_v$. Then, among the$N-1$line segments drawn, no two of them have a common point except at their endpoints.
You are given $M$ permutations of $(1,2,\ldots,N)$: $P^1=(P^1_1,P^1_2,\ldots,P^1_N),P^2=(P^2_1,P^2_2,\ldots,P^2_N),\ldots,P^M=(P^M_1,P^M_2,\ldots,P^M_N)$.
Find the number, modulo $998244353$, of $N$-vertex trees such that $P^1,P^2,\ldots,P^M$ are all good permutations.
Constraints
$2\leq N,M\leq 500$$P^1,P^2,\ldots,P^M$are permutations of$(1,2,\ldots,N)$.- All input values are integers.
Input
The input is given from Standard Input in the following format:
N M
P^1_1 P^1_2 \ldots P^1_N
P^2_1 P^2_2 \ldots P^2_N
\vdots
P^M_1 P^M_2 \ldots P^M_N
Output
Output the number, modulo $998244353$, of $N$-vertex trees such that $P^1,P^2,\ldots,P^M$ are all good permutations.
样例
4 2
1 4 2 3
3 1 4 2
8
12 3
7 9 1 10 8 12 2 6 11 5 4 3
8 10 4 12 11 7 6 3 1 2 9 5
10 4 9 7 5 1 3 11 8 12 6 2
540
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