codeforces#P1312D. Count the Arrays

Count the Arrays

Description

Your task is to calculate the number of arrays such that:

  • each array contains $n$ elements;
  • each element is an integer from $1$ to $m$;
  • for each array, there is exactly one pair of equal elements;
  • for each array $a$, there exists an index $i$ such that the array is strictly ascending before the $i$-th element and strictly descending after it (formally, it means that $a_j < a_{j + 1}$, if $j < i$, and $a_j > a_{j + 1}$, if $j \ge i$).

The first line contains two integers $n$ and $m$ ($2 \le n \le m \le 2 \cdot 10^5$).

Print one integer — the number of arrays that meet all of the aforementioned conditions, taken modulo $998244353$.

Input

The first line contains two integers $n$ and $m$ ($2 \le n \le m \le 2 \cdot 10^5$).

Output

Print one integer — the number of arrays that meet all of the aforementioned conditions, taken modulo $998244353$.

Samples

3 4
6
3 5
10
42 1337
806066790
100000 200000
707899035

Note

The arrays in the first example are:

  • $[1, 2, 1]$;
  • $[1, 3, 1]$;
  • $[1, 4, 1]$;
  • $[2, 3, 2]$;
  • $[2, 4, 2]$;
  • $[3, 4, 3]$.