Find the number of different strings of length $$$k$$$ that you can get by concatenating prefixes of a given string $$$S$$$.
Each test contains multiple test cases. The first line of input contains a single integer $$$t$$$ ($$$1 \leq t \leq 2000$$$) — the number of test cases. The description of test cases follows.
The first line contains two integers $$$n$$$ and $$$k$$$ ($$$1 \leq n \leq k \leq 2000$$$) — the length of $$$S$$$ and the size of the desired strings.
The second line contains a string $$$S$$$ consisting of $$$n$$$ lowercase letters. It is guaranteed that the sum of $$$k$$$ over all test cases does not exceed $$$2000$$$.
For each test case, print a line with one integer — the answer to the problem. Since the answer may be huge, print it modulo $$$998244353$$$.
45 7aaaaa4 4abcd3 3aba7 15abacaba
1832809