题目描述
Problem Description
Given \( n, a, k \), compute:
\[
\sum_{i=1}^n i^k a^i
\]
The answer should be modulo \( 998244353 \).
Input Format
A single line containing three positive integers \( n, a, k \).
Output Format
A single line containing an integer representing the answer.
Sample Input and Output
Sample Input #1
6 4 3
Sample Output #1
1030980
Sample Input #2
233333333 114514 1919810
Sample Output #2
3191086
Notes
Data Range
For 20% of the data, \( 1 \le n, k \le 10^5 \).
For 100% of the data, \( 1 \le k \le 10^7 \), \( 1 \le n, a \le 998244352 \).
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
6 4 3
样例输出
1030980