题目描述
Problem Statement
You are given a prime number P, which you don't like.
Let's call an array of integers $A_1, A_2, \dots, A_N$ good, if it is possible to reorder the elements in such a way that no prefix sum is divisible by P (that is, there is no i with $1 \le i \le N$ and $A_1 + A_2 + \dots + A_i \equiv 0 \bmod P$ after the reordering).
Consider all (P-1)^N arrays of length N with elements from 1 to P-1. How many of them are good?
As this number can be very big, output it modulo 998244353.
Input
Input is given from Standard Input in the following format:
N P
Output
Output the number of good arrays modulo 998244353.
Constraints
- $1 \le N \le 5000$
- $2 \le P \le 10^8$
- P is a prime.
Sample Input 1
2 5
Sample Output 1
12
There are 12 good arrays: [1, 1], [1, 2], [1, 3], [2, 1], [2, 2], [2, 4], [3, 1], [3, 3], [3, 4], [4, 2], [4, 3], [4, 4].
Sample Input 2
4 3
Sample Output 2
8
There are 8 good arrays: [1, 1, 1, 2], [1, 1, 2, 1], [1, 2, 1, 1], [2, 1, 1, 1], [2, 2, 2, 1], [2, 2, 1, 2], [2, 1, 2, 2], [1, 2, 2, 2].
Sample Input 3
5000 99999989
Sample Output 3
51699346
Sample Input 4
2021 307
Sample Output 4
644635349
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分