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Time Limit: 2 s Memory Limit: 1024 MB Total points: 100 Hackable ✓

#13339. You will return like lightning

統計

After defeating Little L in the third game, General Jump allowed you to leave Jump Castle.

Following a long siege of Jump Castle, the Flea King ordered his troops to launch an all-out attack. The battle was fierce, and you made a significant contribution by using the map you obtained while infiltrating the castle to discover a breakthrough—a small, unguarded gate. A tide of fleas and crickets poured through, and the flea-cricket coalition finally succeeded in recapturing Jump Castle, restoring the Flea Kingdom.

At the victory banquet, the flea band played a newly composed song, "You Will Return Like Lightning." The Flea King was in high spirits and posed a problem to the guests, promising a grand reward to anyone who could solve it:

Given a labeled rooted tree where each node is colored either red or green, we call it a "Lightning Tree" if and only if:

  1. The parent $p_i$ of each node $i$ satisfies $p_i < i$.
  2. Each level of the tree contains exactly one red node.
  3. For any node that is not the root, its parent must be red.
  4. Every red node has an even number of green children.

"It can be deduced that the red nodes in a Lightning Tree form a red path from the root down to some leaf node, like a red lightning bolt cutting through the obstacles ahead..." the Flea King described vividly.

Given $k$ and $n$, find the number of Lightning Trees with $n$ nodes and $k$ levels, modulo $998244353$.

This problem is very difficult, and the other guests were at a loss, but you—Volt, a computer expert—realized that this problem could be easily solved with a computer. Once you solve it, the grand reward is yours!

Input

A single line containing two positive integers $k$ and $n$, representing the number of levels and the number of nodes in the tree, respectively.

Output

A single integer representing the answer modulo $998244353$.

Examples

Input 1

2 10

Output 1

9

Note 1

It is easy to see that the tree structure must satisfy $p_2=p_3=\ldots=p_{10}=1$, meaning the first level is node $1$, and the second level consists of nodes $2$ through $10$.

Regarding the colors, node $1$ must be red, and exactly one of nodes $2$ through $10$ must be red, with the rest being green. Thus, there are $9$ possible configurations.

Input 2

3 7

Output 2

65

Input 3

8 14

Output 3

703179

Input 4

529 1453

Output 4

159030840

Input 5

1453 14530529

Output 5

443513052

Input 6

10 1000000000000000000

Output 6

384797525

Constraints

For all test cases, $1\le k\le 10^7$, $k\le n\le 10^{18}$, and $k\equiv n \pmod 2$.

Subtask $k\le$ $n\le$ Score
$1$ $n$ $100$ $15$
$2$ $3\times 10^3$ $10$
$3$ $10^5$ $15$
$4$ $10^7$ $10$
$5$ $3$ $10^{18}$ $5$
$6$ $100$ $15$
$7$ $10^3$ $15$
$8$ $10^7$ $15$

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