// No.2130 分配方法の数え上げ mod 998244353
package main

import (
	"fmt"
)

const MOD = 998_244_353

func main() {
	var N, M int
	fmt.Scan(&N, &M)

	a := modpow(2, N, MOD)

	b := 1
	for i := 0; i < M; i++ {
		a = (a - b + MOD) % MOD

		b = (b * (N - i)) % MOD
		b = (b * modinv(i+1, MOD)) % MOD
	}
	fmt.Println(a)
}

func modinv(a, m int) int {
	b := m
	u := 1
	v := 0
	for b != 0 {
		t := a / b
		a -= t * b
		a, b = b, a
		u -= t * v
		u, v = v, u
	}
	u %= m
	if u < 0 {
		u += m
	}
	return u
}

func modpow(a int, n int, mod int) int {
	m := 1
	for n > 0 {
		if n&1 == 1 {
			m = (m * a) % mod
		}
		a = (a * a) % mod
		n >>= 1
	}
	return m
}