Problem B. Rikka with String

时间限制 3000 ms   内存限制 64 MB

As we know, Rikka is poor at math. Yuta is worrying about this situation, so he gives Rikka some math tasks to practice. There is one of them:

Yuta has $n$ $01$ strings $s_i$, and he wants to know the number of $01$ antisymmetric strings of length $2L$ which contain all given strings $s_i$ as continuous substrings.

A $01$ string $s$ is antisymmetric if and only if $s[i] \neq s[|s|-i+1]$ for all $i \in [1,|s|]$.

It is too difficult for Rikka. Can you help her?

In the second sample, the strings which satisfy all the restrictions are $000111,001011,011001,100110$.
 

输入数据

The first line contains a number $t(1 \leq t \leq 5)$, the number of the testcases.

For each testcase, the first line contains two numbers $n,L(1 \leq n \leq 6, 1 \leq L \leq 100)$.

Then $n$ lines follow, each line contains a $01$ string $s_i(1 \leq |s_i| \leq 20)$.
 

输出数据

For each testcase, print a single line with a single number -- the answer modulo 998244353.
 

样例输入

复制
2
2 2
011
001
2 3
011
001

样例输出

复制
1
4

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