6064：RXD and numbers

RXD has a sequence $A_1,A_2,A_3,\dots A_n$, which possesses the following properties:
- $1\leq A_i\leq m$
- $A_1 = A_n = 1$
- for all $1\leq x\leq m$, there is at least one position $p$ where $A_p = x$.
- for all $x, y$, the number of $i(1 \leq i < n)$ which satisfies $A_i = x ~ and ~ A_{i + 1} = y$ is $D_{x, y}$.
One day, naughty boy DXR clear the sequence.
RXD wants to know, how many valid sequences are there.
Output the answer module $998244353$.
$0\leq D_{i, j}<500,1\leq m\leq 400$
$n \geq 2$

There are several test cases, please keep reading until EOF.
There are about 10 test cases, but only 1 of them satisfies $m > 50$
For each test case, the first line consists of 1 integer $m$, which means the range of the numbers in sequence.
For the next $m$ lines, in the $i$-th line, it consists of $m$ integers, the $j$-th integer means $D_{i, j}$.
We can easily conclude that $n = 1 + \sum_{i = 1}^{m}\sum_{j = 1}^{m}{D_{i, j}}$.

For each test case, output "Case #x: y", which means the test case number and the answer.