AT_abc419_f [ABC419F] All Included
Description
You are given $ N $ lowercase English strings $ S_1,S_2,\ldots,S_N $ , and an integer $ L $ .
Find the number, modulo $ 998244353 $ , of length- $ L $ lowercase English strings that contain all of $ S_1,S_2,\ldots,S_N $ as substrings.
What is a substring?A **substring** of $ S $ is a string obtained by deleting zero or more characters from the beginning and zero or more characters from the end of $ S $ .
For example, `ab`, `bc`, and `bcd` are substrings of `abcd`, while `ac`, `dc`, and `e` are not substrings of `abcd`.
Input Format
The input is given from Standard Input in the following format:
> $ N $ $ L $ $ S_1 $ $ S_2 $ $ \vdots $ $ S_N $
Output Format
Output the answer.
Explanation/Hint
### Sample Explanation 1
Some of the strings that satisfy the condition are `abcz` and `cabc`. `acbd` does not contain `ab` as a substring, so it does not satisfy the condition.
### Constraints
- $ 1\leq N\leq 8 $
- $ 1\leq L\leq 100 $
- $ N $ and $ L $ are integers.
- Each $ S_i $ is a string of length $ 1 $ and $ 10 $ , inclusive, consisting of lowercase English letters.
- $ S_i\neq S_j\ (i\neq j) $