String is a very useful thing and a subsequence of the same string is equally important.
Now you have a string $s$ with length $n$ and a string $t$ with length $m$. Find out the longest subsequence in the string $s$ so that the lexicographical order of this subsequence is strictly larger than $t$.
two integers $n$, $m$ in the first line
（All characters are lowercase letters）
The second line is a string $s$
The third line is a string $t$
Output an integer representing the longest length, otherwise output
9 3 aaabbbccc abc