Problem Statement
We have an $N \times M$ grid. The square at the $i$-th row and $j$-th column will be denoted as $(i,j)$. Particularly, the top-left square will be denoted as $(1,1)$, and the bottom-right square will be denoted as $(N,M)$. Takahashi painted some of the squares (possibly zero) black, and painted the other squares white.
We will define an integer sequence $A$ of length $N$, and two integer sequences $B$ and $C$ of length $M$ each, as follows:
$A_i(1\leq i\leq N)$is the minimum$j$such that$(i,j)$is painted black, or$M+1$if it does not exist.$B_i(1\leq i\leq M)$is the minimum$k$such that$(k,i)$is painted black, or$N+1$if it does not exist.$C_i(1\leq i\leq M)$is the maximum$k$such that$(k,i)$is painted black, or$0$if it does not exist.
How many triples $(A,B,C)$ can occur? Find the count modulo $998244353$.
Notice
In this problem, the length of your source code must be at most $20000$ B. Note that we will invalidate submissions that exceed the maximum length.
Constraints
$1 \leq N \leq 8000$$1 \leq M \leq 200$$N$and$M$are integers.
Partial Score
$1500$points will be awarded for passing the test set satisfying$N\leq 300$.
Input
Input is given from Standard Input in the following format:
N M
Output
Print the number of triples $(A,B,C)$, modulo $998244353$.
样例
2 3
64
4 3
2588
17 13
229876268
5000 100
57613837
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