题目描述
Problem Statement
You are given positive integers N and K. Find the number, modulo 998244353, of integer sequences $\bigl(f(0), f(1), \ldots, f(2^N-1)\bigr)$ that satisfy all of the following conditions:
- $0\leq f(x)\leq K$ for all $non-negative integers x (0\leq x \leq 2^N-1)$.
- f(x) + f(y) = f(x $,\mathrm{AND}$\, y) + f(x $,\mathrm{OR}$\, y) for all non-negative integers x$y (0\leq x, y \leq 2^N-1)$
Here, $\mathrm{AND}$ and $\mathrm{OR}$ denote the bitwise AND and OR, respectively.
Input
Input is given from Standard Input in the following format:
N K
Output
Print the number, modulo 998244353, of integer sequences that satisfy the conditions.
Constraints
- $1\leq N\leq 3\times 10^5$
- $1\leq K\leq 10^{18}$
Sample Input 1
2 1
Sample Output 1
6
The following six integer sequences satisfy the conditions:
- (0,0,0,0)
- (0,1,0,1)
- (0,0,1,1)
- (1,0,1,0)
- (1,1,0,0)
- (1,1,1,1)
Sample Input 2
2 2
Sample Output 2
19
Sample Input 3
100 123456789123456789
Sample Output 3
34663745
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 1
样例输出
6