9875: ABC305 —— G - Banned Substrings
[Creator : ]
Description
You are given a set $S=\lbrace s _ 1,s _ 2,\ldots,s _ M\rbrace$ of non-empty strings of length at most $6$ consisting of `a` and `b`. Find the number of strings $T$ of length $N$ consisting of `a` and `b` that satisfy the following condition:
- $T$ does not contain $s _ i$ as a consecutive substring for any $s _ i\in S$.
Since the answer can be enormous, find it modulo $998244353$.
- $T$ does not contain $s _ i$ as a consecutive substring for any $s _ i\in S$.
Since the answer can be enormous, find it modulo $998244353$.
Input
The input is given from Standard Input in the following format:
```
$N$ $M$
$s _ 1$
$s _ 2$
$\vdots$
$s _ M$
```
```
$N$ $M$
$s _ 1$
$s _ 2$
$\vdots$
$s _ M$
```
Output
Print the answer modulo $998244353$ in a single line.
Constraints
- $1\leq N\leq10^{18}$
- $1\leq M\leq126$
- $N$ and $M$ are integers.
- $s _ i$ is a non-empty string of length at most $6$ consisting of `a` and `b`.
- $s _ i\neq s _ j\ (1\leq i\lt j\leq M)$
- $1\leq M\leq126$
- $N$ and $M$ are integers.
- $s _ i$ is a non-empty string of length at most $6$ consisting of `a` and `b`.
- $s _ i\neq s _ j\ (1\leq i\lt j\leq M)$
Sample 1 Input
4 3
aab
bbab
abab
Sample 1 Output
10
There are 10 strings of length 4 consisting of a and b that do not contain aab, bbab, or abab as consecutive substrings: aaaa, abaa, abba, abbb, baaa, baba, babb, bbaa, bbba, and bbbb. Thus, you should print 10.
Sample 2 Input
20 1
aa
Sample 2 Output
17711
Sample 3 Input
1000000007 28
bbabba
bbbbaa
aabbab
bbbaba
baaabb
babaab
bbaaba
aabaaa
aaaaaa
aabbaa
bbaaaa
bbaabb
bbabab
aababa
baaaba
ababab
abbaba
aabaab
ababaa
abbbba
baabaa
aabbbb
abbbab
baaaab
baabbb
ababbb
baabba
abaaaa
Sample 3 Output
566756841