题目描述
Problem Description
A parenthesis sequence is a string consisting of ( and ). A valid parenthesis sequence is defined as follows:
- An empty string
- A valid parenthesis sequence $ A $ exists, and the string formed by concatenating
(, $ A $ ,)in this order - Non-empty valid parenthesis sequences $ S, T $ exist, and the string formed by concatenating $ S $ , $ T $ in this order
Now, there are $ N $ distinguishable boxes.
You are thinking of putting a valid parenthesis sequence into each of the $ N $ boxes. However, you need to satisfy the following two conditions:
- The total number of
(in the $ N $ boxes is $ M $. - No box should contain a parenthesis sequence of length $2 \times K$.
Find the number of ways to do this, modulo $ 998244353 $.
Two ways are considered different if there exists a box with a different parenthesis sequence in it.
Input Format
The input is given from the standard input in the following format:
$ N $ $ M $ $ K $
Output Format
Output the answer in one line.
Sample Input and Output
Sample Input #1
2 2 1
Sample Output #1
4
Sample Input #2
1 1 1
Sample Output #2
0
Sample Input #3
24 120 30
Sample Output #3
379268651
Notes/Hints
Constraints
- $1 \leq N \leq 10^6$
- $1 \leq M \leq 10^6$
- $1 \leq K \leq M$
Partial Points
- If you solve the dataset satisfying $1 \leq N, M \leq 2000$, you will be awarded $ 10 $ points.
- If you solve the dataset without additional constraints, you will be awarded an additional $ 490 $ points.
Sample Explanation 1
(()), empty -()(), empty - empty,(())- empty,()()for $ 4 $ ways.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
2 2 1
样例输出
4