package main

import . "fmt"
import . "math/big"

func main() {
	var a,b int
	Scan(&a,&b)
	const Mod = 998244353
	n := (a-1) + (b-1)
	x := make([]int, n+1)
	x[0] = 1
	for i := range x[1:] {
		x[i+1] = x[i]*(i+1)%Mod
	}
	y := make([]int, n+1)
	y[n] = int(new(Int).ModInverse(NewInt(int64(x[n])),NewInt(Mod)).Int64())
	for i := range y[1:] {
		j := n-i
		y[j-1] = y[j]*j%Mod
	}
	ans := x[n]*y[a-1]%Mod*y[b-1]%Mod
	Println(ans)
}