# The Assignment

Cefalo SUST Inter Univers...
Limits 1s, 512 MB

Bolt is working at a prominent company called Icefire. He has been given a task for evaluation. The task is about substring triplets. A string $s$ of length $n$ is given at first. To build a substring triplet $(s_1, \, s_2, \, s_3)$, the following procedures are followed ($1$-based indexing):

1. At first, three unique integers $b_1, \, b_2, \, b_3$ $(1 \leq b_1, \, b_2, \, b_3 \leq n)$ are selected

2. Then an integer $p$ $(1\leq p\leq n; \space \max(b_1, \, b_2)+p\leq n+1)$ is chosen such that the following two conditions are satisfied:

• For each $i$ $(0\leq i < p)$, $s_{b_1+i} = s_{b_2+i}$

• If $\max(b_1, \, b_2)+p \leq n$, $s_{b_1 +p} \neq s_{b_2+p}$

Let, $e_1$ be $\min(n, \, b_1+p)$. The substring $s_1$ is the substring $s_{b_1}, s_{b_1+1}, \dots, s_{e_1}$

3. Similarly, another integer $q$ $(1\leq q\leq n;\space \max(b_3,b_2)+q\leq n+1)$ is chosen such that the following two conditions are satisfied:

• For each $i$ $(0\leq i < q)$, $s_{b_3+i} = s_{b_2+i}$

• If $\max(b_3, b_2)+q \leq n$, $s_{b_3 +q} \neq s_{b_2+q}$

Let, $e_3$ be $\min(n, b_3+q)$. The substring $s_3$ is the substring $s_{b_3}, s_{b_3+1}, \dots, s_{e_3}$

4. Finally, the substring $s_2$ is generated. Let, $e_2$ be $\min(n, b_2 + \max(p, q))$. The substring $s_2$ is the substring $s_{b_2}, s_{b_2+1}, \dots, s_{e_2}$

The score of the substring triplet is $p\times q$.

For example, let a string $s$ of length $n=10$ is $\tt{abababcxya}$ and $b_1=3, b_2=1, b_3=10$. According to the conditions above, the value of $p$ will be $4$ and so, $e_1 = \min(n, b_1+p) = \min(10, 3+4) = 7$. So, the substring $s_1 = \tt{ababc}$ from $\tt{ab\underline{ababc}xya}$. Similarly, the value of $q$ will be $1$ and so, $e_3 = \min(n, b_3+q) = \min(10, 10+1) = 10$. So, the substring $s_3 = \tt{a}$ from $\tt{abababcxy\underline{a}}$. Finally, the value of $e_2$ will be $\min(n, b_2+\max(p,q)) = \min(10, 1+\max(4,1)) = 5$. So, the substring $s_2 = \tt{ababa}$ from $\tt{\underline{ababa}bcxya}$. The score of this substring triplet $(\tt{ababc}, \tt{ababa}, \tt{a})$ is $p\times q = 4\times 1 = 4$.

Icefire tells a substring triplet good if the substrings $s_1, s_2, s_3$ are non-empty and lexicographically $s_1 < s_2 < s_3$ satisfies. Bolt has already generated all possible good substring triplets. Now, he needs to calculate the sum of their scores. Can you calculate it for him?

A substring of a string $s$ is a string that consists of some consecutive characters from string $s$. A string $a$ is lexicographically smaller than a string $b$ if either $a$ is a prefix of $b$ and $a \neq b$, or in the first position where $a$ and $b$ differ, the string $a$ has a letter that appears earlier in the alphabet than the corresponding letter in $b$.

## Input

The first line contains an integer $T\space(1\leq T\leq 10^5)$ — the number of test cases.

The second line contains an integer $n\space (3\leq n \leq 5\times 10^5)$ — the length of the string.

The third line contains the string $s$ — which consists of only lowercase English letters.

The sum of $n$ over all test cases will not exceed $5\times 10^5$.

## Output

In each test case, print a single integer in a line, the sum of the scores of the good substring triplets. As the answer can be very large, print it modulo $998244353$.

## Sample

InputOutput
2
10
abababcxya
5
zzzax

19
2


In the second case, the only good substring triplet is: $\tt(za, zza, zzz)$. Here, the value of $p$ and $q$ are $1$ and $2$ respectively. So, the answer is = $(p\times q)\mod 998244353$ = $(1\times 2)\mod 998244353$ = $2$.