题目描述
Problem Background
Clouds drift, seas change into mulberry fields.
Before the clouds lies only a blurred vision.
In the hazy appearance, it sees small pearls, some glowing with colorful lights. These pearls were left by a rabbit, each pearl having a color, randomly one of $D$ colors.
The cloud wants to put these pearls into small bottles, each bottle exactly holding two pearls. However, it has a requirement: each bottle must be filled, and both pearls in the same bottle must be of the same color.
The cloud hopes to obtain at least $m$ filled bottles. It wonders what the probability is that its wish can be fulfilled.
Problem Description
There are $n$ uniformly random variables within the range $[1, D]$.
Determine the probability that at least $m$ bottles can be chosen such that there exists a scheme to select some variables and place each selected variable into a bottle, satisfying that each bottle contains exactly two variables of the same value.
Output the value of this probability multiplied by $D^n$ modulo $998244353$. For the modulo part, refer to the first problem for instructions.
Input Format
The input consists of a single line with three integers $D, n, m$ separated by spaces.
Output Format
Output a single integer, representing the sought probability multiplied by $D^n$ modulo $998244353$.
Sample Input and Output
Sample Input #1
2 2 1
Sample Output #1
2
Sample Input #2
8 10 4
Sample Output #2
301103104
Sample Input #3
998 1000 500
Sample Output #3
762913089
Notes
Sample 1 Explanation
Case 1: The first variable is 1, the second variable is 1.
Case 2: The first variable is 1, the second variable is 2.
Case 3: The first variable is 2, the second variable is 1.
Case 4: The first variable is 2, the second variable is 2.
Among these, cases 1 and 4 can place both variables in one bottle.
In cases 2 and 3, the values of the two variables are different, so they cannot be placed in the same bottle.
Test Data Constraints
All test cases satisfy $0 \leq m \leq 10^9, 1 \leq n \leq 10^9, 1 \leq D \leq 10^5$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分