Little H initially has a string $$$s$$$ composed of lowercase letters.

The charm value of a string is defined as the number of essentially different substrings.

For example, $$$\texttt{aaa}$$$ has only $$$3$$$ essentially different substrings: $$$\texttt{a}, \texttt{aa}, \texttt{aaa}$$$, while $$$\texttt{aabb}$$$ has $$$8$$$ essentially different substrings: $$$\texttt{a}, \texttt{aa}, \texttt{b}, \texttt{bb}, \texttt{ab}, \texttt{aab}, \texttt{abb}, \texttt{aabb}$$$.

He thinks the charm value of the initial string $$$s$$$ is too low, so he duplicates $$$s$$$ $$$m$$$ times and concatenates them together, trying to obtain a string with a higher charm value.

However, after he finished duplicating, he found that he could not accurately calculate its charm value. Please help him calculate the charm value of the duplicated string. Since the answer may be large, you need to output the charm value modulo $$$998244353$$$.